Native English speaker here.

I think what you're seeing is partially due to the misperception that you described, and partially due to the relatively (and, yeah, variably) anti-authoritarian nature of anglo-saxon culture.

Also, I'm not sure the idea of trying to keep loanwords out of one's language makes much sense to someone who grows up speaking a language composed almost entirely of loanwords. So that might be why you see so much fixation on that aspect of the Académie.