Come to think of it, one significant reason why I became apathetic with regards to the activities the "ambitious kids" did in high school is that they annoyed me so much. The idea of spending a lot of time with the kind of people who were in Volunteer Club in high school is pretty unbearable.

Yeah, it's that sort of "annoyance" and "ick" that's the sort of disapproval I'm talking about. When you have one attached to a group stereotype, it means you'll have an aversion to expressing any characteristic of yourself that "means" you'd be one of "them".

For example, at one point I found vegans annoying, and this made it difficult for me to switch to a mostly-vegetable diet, because then I'd be one of "them".

Unfortunately, this ingroup/outgroup signaling by our brains has almost nothing to do with actual morality OR personal utility. Our brains will rationalize like crazy to give us high-sounding reasons for our annoyance, to make us feel we're taking a principled stand somehow, but in actuality the whole thing is moot. You approving of the "ambitious kids" (or your status-cheating valedictorian friend) as people won't actually contribute to some sort of moral decay in society, no matter how much your tribal brain makes you feel like it is.