You're reading too much into this, I think. Bad kids do exist. Be compassionate, but do not encourage involvement with them.
I have really really profound regrets about not doing this myself, with my kids.
I have really really profound regrets about not doing this myself, with my kids.
I don't think there's tension in what you're saying: Yes it's very much ok to avoid people when they're being mean, heartless, etc. At the same time that doesn't mean they're "bad" or enemies.