Wow - bit overblown all in all. While it sounds like the quinoa guy is kinda a jerk, I'm not seeing any proof of racism on his part. He just boosted a legitimate news article (the Fediverse servers being seized that popped up yesterday) posted by this Eris character, who had been flagged as a racist troll in the past. This isn't confirmed or denied in the various posts aside from a profile link on thebadplace.com - which has no information aside from a few racist tags on that profile (can't tell who the profile is for).
This sounds more like the admins got snippy at each other in off-site discord drama and decided to take their toys and go home. Interesting for the /popcorn, but hey, if mastodon.art doesn't wanna play with firefish, that's their decision, regardless of the reasoning, end of story.