Reconciling metta & avoiding fools/immoral people

There is no problem with giving Val an Answer out of compassion without associate and to wish him "may he be able to give causes for long term happiness by himselves with ease" then, knowing he would not ease be able to receive any supportive advice.

No need to associate with him or with his ideas at all and avoid it.

Here is an example of what you have asked (SN3.18):

The teaching is well explained by the Buddha. But it’s for someone with good friends, companions, and associates, not for someone with bad friends, companions, and associates.

Let's look at "bad". Suppose you ask your friend, "are you good or bad?". Would your friend say "I am good" or "I am bad"? Probably not. And have we met anyone who says "I am totally 100% evil and bad?" Well, perhaps one should indeed avoid such people.

But really, it is far more likely that your friend would not be so clear. It is likely that a friend would answer "I try to be good". Or "sometimes I am bad".

So now the situation you have asked turns out to be quite complicated if taken literally as ruler to hold up and measure friends. This one PASSES. That one FAILS. 😱 Perhaps we should not do this judging of friends.

To be someone with good friends is to be with people who strive for goodness. It is to be with people:

who refrain from killing living creatures, stealing, and committing sexual misconduct. They refrain from speech that’s false, divisive, harsh, or nonsensical. And they’re content, kind-hearted, with right view. --DN23

This also means that if we hang out with bad friends, we will worry about being killed, being stolen from, being sexually mistreated, being told lies, or being yelled at or being told just plain nonsense.

It is therefore kinder to all if we spend time with good (see precepts above) friends striving for goodness.

The Buddha was able to deal with serial killers such as Aṅgulimāla, who became his disciple and therefore a good friend. We ourselves might die attempting the same, so perhaps we should do what we can to be good with the friends we have and make.

The Buddha repeatedly said to avoid ignorant, immoral people as much as possible, but isn't this - at least a little - opposed to kindness? I associate kindness with being benevolent, caring & somewhat open. Am I missing here something?

No, they have nothing be opposed to each other. Actually, they support each other.

The practitioner can do metta to every person, including the immoral people, every time because Metta is mental meditation, but the practitioner shouldn't be very familiar with them because the practitioner can derive their bad behavior.

We help and support a cat, e.g. giving food, but we shouldn't be very familiar with a cat because the cat can't teach us the four noble truth.

Avoiding the ignorant person is not worry or scary. it is understanding of the effects of each fellowship.

The practitioner still wants to give happiness to the ignorant person every time, but the practitioner is just careful to keep the distance between practitioner-self and the ignorant person.

Metta is wishing to give happiness to the other living life(s).

What is that life?

The life is the aggregates in dependent origination cycle, so sometimes life has a wholesome mind and it's mental&physical factors, but sometimes life has an unwholesome mind.

Metta-mind doesn't care about life's mental state. Metta-mind cares about the entire of which is called "living life".

Mind that voiding from ignorant, immoral people is focusing at the mental state. We don't want to derive any bad habit from the ignorant, immoral people, so we should avoid being close with them.

For the example:

I have the only mother, so I can do everything to make her happy, but I have to avoid to study chemistry with her because she is ignorant of it.

I give some food to the immoral victims because I am so sorry with their suffering however I do not support their previous immoral and bad behavior. I am not going to be immoral and to have bad behavior like them.

I think it is a very wise advice. Immoral, ignorant people are selfish, narcissistic, unable to feel guilty and can harm others easily. The immoral people are also "fool" so I think the word "fool" refers to the immoral people. But this foolishness is "generally" not about having a low IQ, but it is about how a person sees life in general, is completely ignorant in their relationships with others and being completely identify wth the evil nature of humanity. Also "immoral" means who are prone to harm others easily. Often you will see that many "immoral" people are absolutely moralists but because these people are completely enslaved by the dark nature of humanity and because they don't have any awareness(other than being able to walk in the street or drive a car etc) they can do the evil actions that they criticize very easily. Also they have wrong perceptions of what is moral and what is immoral, what is good and what is evil too. So these people can do extremely evil things but think that they are doing the "moral" thing without feeling guilty.

Not associating with fools, Associating with the wise, Honoring those worthy of honor; This is the greatest blessing.

The beings who are in same level of frequency comes together naturally

Beings of low dispositions come together & associate with beings of low dispositions. Beings of admirable dispositions come together & associate with beings of admirable dispositions.

Vulnerability grows as you move forward in the Buddhist path. Vulnerability is being completely open to every possibility and form in life. But it doesn't require you to willingly associate with immoral, ignorant people and let them pull you down to their darkness. Just like the sun, is completely open and vulnerable and gives sunshine to every form in the world, is far enough to protect and take care of itself. Kindness and caring isn't about hugging people who have the capasity to stab you in the back anytime. Love is realizing that underneath of the evil nature of humanity, there is Buddha nature, Emptiness. Also every form is empty. No form is real in their essence. But most humans are not aware of it and they are completely identified with their forms. So when you recognize that humans are ignorant, don't have awareness of their own essence, you start to have compassion and love towards everyone. But as a "form" every human is naturally prone to do evil things because there are many layers of ignorance and dark energies in the human mind that comes from maybe millions of life times. Love is not about liking or being friends with everyone.

There is a funny sutta where Punna wanted to live among bad people and the buddha questionned him on his skils

"Lord, there is a country called Sunaparanta. I am going to live there."

"Punna, the Sunaparanta people are fierce. They are rough. If they insult and ridicule you, what will you think?"

"If they insult and ridicule me, I will think, 'These Sunaparanta people are civilized, very civilized, in that they don't hit me with their hands.' That is what I will think, O Blessed One. That is what I will think, O One Well-gone."

"But if they hit you with their hands, what will you think?"

"...I will think, 'These Sunaparanta people are civilized, very civilized, in that they don't hit me with a clod.'..."

"But if they hit you with a clod...?"

"...I will think, 'These Sunaparanta people are civilized, very civilized, in that they don't hit me with a stick.'..."

"But if they hit you with a stick...?"

"...I will think, 'These Sunaparanta people are civilized, very civilized, in that they don't hit me with a knife.'..."

"But if they hit you with a knife...?"

"...I will think, 'These Sunaparanta people are civilized, very civilized, in that they don't take my life with a sharp knife.'..."

"But if they take your life with a sharp knife...?"

"If they take my life with a sharp knife, I will think, 'There are disciples of the Blessed One who — horrified, humiliated, and disgusted by the body and by life — have sought for an assassin, but here I have met my assassin without searching for him.' [1] That is what I will think, O Blessed One. That is what I will think, O One Well-gone."

"Good, Punna, very good. Possessing such calm and self-control you are fit to dwell among the Sunaparantans. Now it is time to do as you see fit."

https://www.accesstoinsight.org/tipitaka/sn/sn35/sn35.088.than.html

I think it's a matter of degree, not entirely black-and-white -- how stable you are, how much contact there is between you and of what type, etc.

A monk's giving a formal dhamma talk to a polite audience might be not-very-adversely affected, for example.

Whereas, conversely, your joining a criminal gang would be maybe not so harmless.

It might possibly be a conceit, too, to imagine that you're better than someone else; that you're able to benefit them even when they don't already benefit themselves; that your goodness is stable and is independent of the situation you're in (the company you're with); and so on.

It's good to want to be kind, but you might beware of pathological codependency for example -- which might seem well-intentioned but maybe isn't beneficial (and therefore not actually kind, or not skillful).