I said "seek out peer groups in which their desired/target behaviors are normal".

In other words, the presupposition is that you've already come to the conclusion that you want to have those beliefs or behaviors, because you evaluated them before choosing to participate in the group in question.

Ah, there's the kicker. I thought her advice was good, but I had never realized that I could check out groups' behaviors in order to see if they're good or bad, rather than just blindly joining a group and hoping it's a good one. This should change my behavior in the future.