Why aren't there omnicidal Buddhists?

Would't people, if all exchange-members would be deleted, not seek for another birth, where ever possible? Some in other internnet realms, some outside, some in intranets, some animal-like, some as hungry ghosts, hell beings...

Nihilism isn't the Buddhas teaching and as long as there is craving out of not-knowing, beings wander on. Covid 19...20... 1017... no way, even for oneself, if thinking body is the self.

Sure there are also crazy "Buddhist" possible same confused thinking as good Nick, so take care!

There is an old movie that I will not name here, nor mention the actors. In this movie, the plot is that a psychiatrist talks to a troubled child, who later reveals to him that he can see and talk to people who have died (ghosts). He tries to treat the child, and get him cured of his delusions. At the end of the movie, there is a plot twist. It was the psychiatrist who was deluded and not the child. The psychiatrist discovers that he is not who he thought he was.

Similarly, people think they exist and Buddhism teaches that persons are reborn and suffer if they don't attain Nirvana, so instead they should strive and attain Nirvana so that they cease to exist.

However, there is a plot twist. Actually, there was no standalone permanent self or individuality all along. The enlightened disciple discovers he is not who he thought he was.

All phenomena is not self. The self is just temporary mental idea that arises and ceases depending on conditions. The self a minute ago is not the same as the self now.

Enlightenment is not about ceasing to exist to end suffering. Enlightenment is about understanding reality, purifying the mind and mentally letting go of the things that causes the arising of (mental) suffering. Enlightenment is about finding the only stable and permanent source of peace and bliss - Nirvana.

"Existence" refers to the ephemeral and dependently originated mental models of reality that is reified and not ultimately true. It is that which ceases for the enlightened. It is not that an individual who formerly existed, who now ceases to exist.

Literally, because you'll be reborn.

If you don't believe in rebirth, then because impermanent pleasures can be enjoyed without attachment and these outweigh the suffering all conditioned things bring with them. Same as anyone.

the Buddha declares that all sankharas [conditioned things] are suffering (sabbe sankhara dukkha). However, they are suffering not because they are all actually painful and stressful but because they are stamped with the mark of transience: “Having arisen, they then cease.” Because they all cease, they cannot provide stable happiness and security.

There seems to be a few misunderstandings on this board. Existence is the root of all suffering, but is not only composed of suffering.

What are “Conditioned Things” in Buddhism? mentions a Theravada verse used at funerals:

Impermanent, alas, are conditioned things! Their very nature is to arise and vanish. Having arisen they then cease. Their subsiding is blissful!

As posted in this comment I think this question is similar to the several topics tagged suicide -- which are also about the idea of killing, all the same counter-arguments apply here -- and topics like this asking about "antinatalism".

Buddhists have addition reason not to kill others -- it's directly contrary to not harming others.

It's contrary to the first of the five precepts which summarise a code of morality.

There are famous passages from Buddhist scripture like the Dhammapada:

129. All tremble at violence; all fear death. Putting oneself in the place of another, one should not kill nor cause another to kill.
130. All tremble at violence; life is dear to all. Putting oneself in the place of another, one should not kill nor cause another to kill.

As for the idea that "existence is the root of suffering" see for example the topic, Did the Buddha really say that "life is suffering"?

why aren't there any murderous Buddhists

There probably are, depending on definition.

For example Wikipedia says that the cult behind the Tokyo subway sarin attack was considered kind of Buddhist:

Shinrikyo Aum is a syncretic belief system that draws upon Asahara's idiosyncratic interpretations of elements of early Indian Buddhism and Tibetan Buddhism, as well as Hinduism, taking Shiva as the main image of worship and incorporating millennialist ideas from Christianity, Yoga, and the writings of Nostradamus. Its founder, Chizuo Matsumoto, claimed that he sought to restore "original Buddhism" but employed Christian millenarian rhetoric. In 1992, Matsumoto, who had changed his name to Shoko Asahara, published a foundational book, declaring himself to be "Christ", Japan's only fully enlightened master, as well as identifying himself as the "Lamb of God".

Asahara's purported mission was to take upon himself the sins of the world, and he claimed he could transfer spiritual power to his followers and ultimately take away their sins and bad deeds. While some reject Aum Shinrikyo's claims of Buddhist characteristics and affiliations with Buddhism, other scholars refer to it as an offshoot of Japanese Buddhism, and this was how the movement generally defined and saw itself.

Aleph (Japanese cult)

There have been other historical instances of violence in nominally Buddhist societies -- like, I don't know, samurai, wars, civil wars, anti-immigrant ethnic cleansing.

I see non-violence as so fundamental to Buddhism that I personally apply No true Scotsman to the topic, saying that such thinking or action by (my) definition not Buddhist or contrary to Buddhism.

Buddhism does warn though about, for example, ignorance and delusion -- that (not to excuse it) there's been some ignorance or confusion about what's right, and so on.

Or possibly you might see it as being something like Christian "sin", i.e. contrary to the official doctrine, but found nevertheless in some smaller or even greater extent in some practitioners -- and in people who claim to be, or who "identify as", or who are members of a culture or society which identifies as or is influenced by "Buddhism" or which includes some of its historical iconography etc.

Well, I suppose the initial problem (from a reincarnationist perspective) is that once one is on the karmic wheel the only way off is live and attain nirvana. If all living beings were killed, then we would all be stuck in some metaphysical quandary — one of the Buddhist hell realms, the hungry ghost realm, the bardo state, etc — because our attachments to sensual life would be unable to find any release. At least, we'd be stuck there until the world evolved to provided us with a new vehicle for embodiment. No one really wants to be stuck in one of these realms, so trying to destroy the cycle of human rebirth is completely self-defeating.

I heard this statement by Beth Upton and saw it in the suttas too to some extent: rebirth is the caveat with the kill-all approach. Killing alone wont provide Nibbana but lead to less than ideal rebirths, given that no human incarnation is possible any more, e.g. as animals or devas, if you're lucky. Also it is said that the human existence is especially good for working towards Nibbana, because a broad range of experiences is available, from the hellish to the heavenly. So its overall good to keep the human plane intact.

She also said that it isn't really obvious up-front why avoiding existence might be a good idea, but if you shred your mind meditation-wise to a clear perception of dukkha associated with its every minute movement, it might appear more attractive. It also might become apparent in an experience of deep calm that gives a contrast to the intensity of usual mental operation, e.g. in concentrative meditation or in a near death experience.

And, eventually, its not about our everyday existence, its about craving that perpetuates activity, so to speak. People at the final goal of the meditative development continue to live in this world in a supposedly very nice state of mind devoid of itchy impulses. The keyword for that stuff is Arahant.

I'm not a believer btw., I just pass on what I've heard.

existence is the root of suffering

no, it's not. The official definitions are "unsatisfied thirst is [mental] suffering", "craving and grasping is the origin of suffering", "i-making is the root of suffering" and "ignorance is the ground of suffering" (My wording here should be accurate enough, the originals are in the Pali language so any translation will be approximate anyway).

To be absolutely honest, Buddha did say "however small, a piece of shit stinks and [individual] existence is the same - however short it is full of suffering". But he said it specifically about the confused existence of regular uninstructed worldlings, full of ignorance, i-making, craving, and the unsatisfied thirst.

Buddhists seek to end suffering by attaining a state of spiritual enlightenment that, after death, will cause them to cease to exist instead of reincarnating ("Nirvana").

Not really. That's the fairytale version for those students who can't take the full truth (yet).

The full truth is that Nirvana is a metaphor for "the Right View" aka "liberation of heart by wisdom leading to dispassion", where the "mental suffering" ends through essentially achieving the level of insight when one's expectations no longer clash with reality. The resultant state of conflict-less suchness (things being understandably as they are and not otherwise) is the true Enlightenment and Nirvana.

Now, in light of these definitions your question simply has no base in reality. It's like asking about the ethical issues with Santa keeping elves as slaves. There's no Santa nor enslaved elves, so the question does not apply.

I've never heard of any Buddhist sects that actively seek to murder everybody. Why is this the case?

I imagine when the Buddhist neophytes come to their Buddhist teachers saying "I have a breakthrough idea, let's just kill everybody" - the teachers who know what Nirvana is really about immediately pour a bucket full of ice-cold water over their heads and send them back to keep on meditating :)

As to why those Buddhists that don't have a teacher who'd know Nirvana isn't oblivion wouldn't do the same, essentially, even if you wipe out all life on Earth there are other worlds and other universes to be reborn into. Plus, and the most obviously, killing is bad karma that makes one get reborn in hell.