First of all, I'd like to establish that the way you propose people act insults every single person's ability to act on their own accord. You seem to put much more emphasis on the external pressures than they deserve and disregard the importance of decision in any action. Certainly, their effect on our mind is undeniable - it would be foolish to suggest otherwise - but it's not everything there is to acting, especially to acting in ways less desirable.

Yet free will and the environmental effects one endures affect us on a conscious level and biological level. There are varying and unchanging ways that our environments affect us as people, and even as far as affecting our children. I never said that it was "everything" as you put it. Don't put absolutes where they aren't.

Secondly, the decision-making is important for acting in any way. Existentialism establishes that everything is a choice, even not making a choice. I find this idea empowering, because it reveals that, like many things we think of ourselves, our perceived inability to control our lives and ourselves is just that - a perception, a feeling. It implies that human beings are, indeed, very powerful, emotionally and mentally, and are capable of persevering through the worst adversities of life without bending or succumbing to the ill event. It's incredibly hard to survive the deepest pits of internal Hell, I grant you, but it's not impossible, either.

I feel I need to reiterate this again, but I never disregarded the biological inclinations, just that the environment plays a very strong role in deciding who we become. In this you mention perception which is another aspect of self that is heavily affected by our environment. Our perception of self, of others, of institutions, of religion, of any concept under the sun.

With that in mind, I'd like to refer to a concept I've mentioned earlier. You misunderstood it as the power dynamic between people in a society. What I referred to, instead, was the feeling of power - or, more specifically, the feeling of control over one's life and oneself. It is through lacking it that we feel like doing evil, however petty or big. If a person feels in control of their lives - that is, of the events and, more importantly, experiences that make said life - there's no need for them to commit any sort of crime because there's no need for establishing this control. It's through the collision of the ideals - "That's what I want to have" - and the reality in which we don't seem to even have a clear way of having it that evil motives arise; it's ego fighting back for being important once again as it was in the childhood. It is this power that we desire: to change the circumstances that don't satisfy us.

What is the self? What is one's life? What are either of those concepts without interaction? Society is one giant interaction, one that affects ourselves and everyone we interact with. Essentially what you are saying is when we cannot control certain aspects of our environment we act out which would mean? That the environment plays a strong role in deciding who we become as people, yes? All of this is in reflection to the environment we exist in. In nothing you mentioned does it operate outside of society, interaction, or our environments. Everything you've mentioned is reformed and changed by the environment on a constant basis.