Using "blacks" is certainly a choice
I've been in these spaces too and he's right. I remember the amount of hate you would get from just being a black cosplayer. And there's a wide spectrum of people at these conventions: the nerds in the gaming hall that don't wear deodorant or take showers that spend all day there, the cosplayers, the autograph collectors, the shoppers, the dudes that be at the hentai rooms (if they have them) and the people who have these interests and just there for a good time. Most convention goers are in the latter and are there to socialize.
I use black because I am black and I can speak with authority on the black gamer, nerd, sci-fi and comic space of the 90s and 00s. I was there. My dad took me with him to trek conventions in the late 80s. There were spaces in those conventions where is fellow blacks sought each other out and made friends and connections.
I always joked on cosplayers I hate that shyt and think it's attention seeking. But I hate it for everyone. You ignore that initially cosplaying was a small segment within the larger nerd culture that gradually got acceptance from the whole.
But now I know OG cosplayers who hate what it has become especially how casual women use it to over sexualize characters for attention. It used to be a source of pride in how detailed and how much care was taken. Now it's about sexualization.
Yeah nerds always had geeks and dorms in proximity, they were tolerated as they still were part of the general culture.
They have been pushed out of fandom in most segments and have had to build their own groups. Sad that black fandoms have to do the same and so quickly