Hello and welcome to steemit! This was an interesting read. Having a kid of my own and growing up somewhat like yourself, I can totally relate.
The problem is that prejudice works both ways and it is always faulty. You cannot treat everyone with kindness and expect them to respond accordingly. The same goes for the opposite.

I believe that the "correct" approach is to treat everyone "neutrally" until you decide based on critical thinking and by the passing of time on if they deserve your kindness. There are all kinds of people out there, exposed in all kinds of situations. You could never know if someone's self interest will work against you. Most probably it will. And this is more common that we realize. It is part of human nature. Self preservation, search for happiness, tendency for competition e.t.c. almost work automatically.

I hope this all makes sense. English is not my native language.
Talk to you soon.