The long and short of it is, One of the lemmy.world admins demoted a mod of the vegan community over a comment about how cat can be fed a 100% vegan diet with supplements and the cat will be fine.
Based on the post they were spreading misinformation and being really unsightly, calling not vegans things akin to slurs like "meaties" or some shit. I don't know the full story though.
Vegan 2.0 was released recently and the attention it received led to a private equity buyout. Vegan® is now a trademark term and you need that ® or it's in violation. I hear they are about to release a line of fake-vegan® meat for people who want to look vegan but like the taste of cow.