TL;DR: it was a pejorative, then it was reclaimed, then it fell out of fashion, then it returned as a pejorative on internet message boards, except English speakers browsing the Japanese internet didn’t realize that was a pejorative and thought bara just meant hairy, muscled gay dudes. And now we’re here!
Men’s Yaoi is just Bara
The history on why we call it bara in English is pretty wild: https://en.wikipedia.org/wiki/Bara_(genre)#Etymology
TL;DR: it was a pejorative, then it was reclaimed, then it fell out of fashion, then it returned as a pejorative on internet message boards, except English speakers browsing the Japanese internet didn’t realize that was a pejorative and thought bara just meant hairy, muscled gay dudes. And now we’re here!