I don't understand bodhicitta

This question is tied to self-view. At earlier stages of practice — before one has started to get the emptiness of self-view — the question of the self's relationship to the world is troubling. Some believe that the self should be extinguished to escape the wheel of (a personal) karma; others believe the self should be retained as a fiction to help others escape their own (personal) karma; yet others (outside of buddhism) hold other beliefs. But all of these are ways the self establishes identity and perpetuates itself. The beliefs are not real.

When one sees that 'self' is an empty concept, one starts to see that there is nothing 'personal' about karma, and then the goals of Theravada and Mahayana become the same: liberation from karma. It makes no sense to distinguish between 'our' karma and 'their' karma; to free oneself is to free others, and vice-versa. These are merely different approaches, a difference that has meaning to those still attached to identity, but not to those who've left the attachment behind. To extend the common metaphor, there are many different boats that can get you across the river, but whichever gets chosen will ultimately be left behind on the far shore.

So what is the real scope of bodhicitta

It is actually a multilayered concept.

Firstly (for Mahayana) generating (what I know as) Aspiring Bodhicitta (which is a general wish to be free from samsara on the behest of all sentient beings) when one does dharma study and practice creates much more "merit" than if one does not create this desire or only created a desire to be free from samsara for oneself while/before studying and practicing.

Secondly, creating Aspiring Bodhicitta creates the karma and proclivity towards compassion so that eventually, spontaneously, one attains (what I know of) Engaging Bodhicitta this "actual" Bodhicitta IS the Bodhicitta that will be the drive, forever more, to seek liberation (to become a Buddha, not an Arhant) solely for the benefit of all sentient beings. When one actually experiences this unique mindstate, Engaging Bodhicitta, this is the mindstate that the Buddha himself experienced which propelled him forth to become a samosambuddha, who of course was able to help (at least) sentient beings (humans) in this world system. Then like how the Buddha mentioned of himself before he was liberated, after this Bodhicitta, one becomes a Bodhisattva, a person destined for buddhahood.

So in laymans terms, having a general desire to become a Buddha when you do dharma practice or study eventually will lead you a powerful internal experience where you will have true conviction (motivated by compassion for all living beings) that you will help them become liberated, by becoming a Buddha for their sake. At that point forward, you are then a Bodhisattva.

Unfortunately it seems quite a few sects of Mahayana, or even possibly all, but I am thinking specifically of Tibetan Mahayana, because of Gampompas egotistical comments based of the lotus sutra parable of the burning house, there is disdain for the "Hinayana" the "lesser path" of actual disciples of the Buddha, Arhants who are seen as not truly liberated and not free from samsara, that only a Buddha, via attaining the Engaging Bodhicitta is actually free. For them nibbana is not liberation, there is still more to do.

So one would assume that the people who put so much stock into Bodhicitta also have the intellectual delusion that only via attaining Engaging Bodhicitta and going through the 10/16 bhumi can they themselves be liberated from samsara.

Personally I feel that this entire concept was created by "lesser" men, not taught by the Buddha himself and seeing there was no Buddha around to verify these concepts, they are essentially fiction or philosophy created by possibly puttajhanna, or path sotapannas in various Buddhist countries in the past. (assuming a fruit attainer sotapanna...onwards would already know the path to liberation as they have seen the goal so would never add to or change the Buddhas teachings, creating an entire new concept)

If one scrutinises Bodhicitta in the framework of Buddhas teachings, dependant origination, 5 aggregates and 2nd noble truth specifically, it seems to me that Bodhicitta is a mistake. A virtuous desire, but a desire non the less. It seems to me that Bodhicitta is in fact bhava-taṇhā

I also do have practical experience with both types of Bodhicitta as I originally studied and practice Mahayana, just mentioning it so that you may take this as not purely academical or intellectual conclusions of the concept.

There is also a paradoxical statement in the Lotus sutra (I forget where, but possibly chapter 2) where the gist is that when one attains a high level on the bodhisattva path and understanding of emptiness one sees that there are no actual beings to have compassion for, in turn, no beings to save, negating Bodhicitta completely and in turn negating ones own "Bodhisattvahood". The concept is blasély brushed over with "lol just have compassion for them anyway" or something in that vein.

Which for me is illogical and goes "against" the core function of what the Buddha taught being logical reality based upon the empirical evidence anyone is able to obtain through being scientific within their own mind. Essentially a belief system! Something the Mahayana is conflicted with, because of being intertwined with pagan, hindu, and colloquial belief systems.

This is not an answer but just a note to the question....

As per my understanding so far, unless and until one realizes that everything boils down to person's own dukkha, one won't be able to free.

Doesn't matter if it's bodhicitta or Bodhisattva.

Yeah, they can continue to try to benefit world or try to make circumstances better for deep meditation, but until they realized dukkha is there in everything, this suffering cycle won't stop.

For example, realization at physical body form can be at sensational level or at mental level, in citta body form it could be at dhamma level (not sure) or at mental level or at pleasing ignorance level..

So no matter, how much one tries to do good for outside world or try to put others or redirect others towards samatha, liberation will only be realized upon realization of dukkha, origin and reasons behind dukkha, resolution/ cessation of those origins and reasons, path for that resolution of origins.

Leaving behind anyone of them would also lead back to dukkha.

Only question left is, "how exactly to lead to these 4 points". So, there could be various ways and experiments and most likely successful would be the one having most samatha with good process (5 precepts from body to citta to dhamma level) to that samatha.

These ways might be the fulfillment of paramitas.

Bodhicitta quite simply means to see things like the Buddha would have seen them.

In the basic sense, it means to be extremely empathetic and sensitive to suffering experienced by other beings. This empathy automatically translates into natural unforced tendency to avoid harming or hurting other beings, and to protect them from harm whenever possible.

When applied to the Buddhist Path, this wish to protect becomes an aspiration to get to the bottom of The Big Mystery of Enlightenment, in order to become capable of truly helping the sentient beings at the most fundamental level as opposed to only providing superficial tactical help.

Finally in the post-Enlightenment, to see things like the Buddha means to see things with the same understanding, to directly see the True Natural Dharma, which of course includes seeing Anatta and Shunyata (Emptiness), among other things.

I see the points you made in your question: why wish for Enlightenment to be able to teach others if we already have the Buddha's teaching? Why have a separate concept for what seems very similar to Brahma-Vihara? Why have a separate word for a Boddhisattva? Why help others if each is his own refuge?

To these I answer so:

Wouldn't it be awesome to be able to teach from the first hand realization as opposed to teaching from theory? Wouldn't that be more productive and more beneficial to the beings who's pain we want to reduce?

Why get stuck on the metaphor of Brahma Abode (=Brahma's perspective) that Buddha repurposed from religious beliefs popular at his times, as an illustration that would make sense to his contemporaries, if we can refer to Buddha's mind as a perfect role model for his students?

Or perhaps you can coin your own concepts picking your own metaphors. After all, it's the essence that matters while the words are just teaching aids.

When one is committed to finding and passing on the essence, as opposed to finding and passing on the words, we call such person a Bodhisattva.

True, Bodhisattvas can't bestow Enlightenment onto people, but they can try to help as much as they can. Why help at all? Bodhicitta! It is painful to see all this suffering, and helping others with Dharma provides a relief. And when the next generation of students learns to see, they too see the suffering of others and have the spontaneous wish to help. It's a kind of virtuous circle, the Wheel of Dharma.