Over the last week I could swear I've seen way more 
types suddenly throwing around the word troglodyte left right and centre
The fgc is profoundly sexist, but it's very multiracial, with a particularly large proportion of black members, including the NB person who is currently held as the best in the genre, sonicfox. It's possible that I just don't know the origin, but I wouldn't guess that it was something anti-black because then there would probably be more pushback against it.