A friend of mine from college said he was accused of "acting white" for trying to get good grades in school when he was younger. I forget if it was Detroit or Minneapolis, but either would be likely. Minnesota has (or at least had) the US's largest gap between racial achievement in education.

More broadly speaking, even when I was growing up being a "nerd" (what the kids would say instead of bookish) was always uncool. It's practically a trope in American media since we had media as such. Smart, brainy kids are juxtaposed against the "cool" jocks and popular crowd.

Gen X Anglosphere