I wondered the same - like Ada is one of if not the most level-headed person on the entire Threadiverse. But when I asked elsewhere I simply got downvoted bc Reddit Lemmy gonna Reddit Lemmy, I guess.

The author explains his reasoning here: https://lemmy.world/post/49817942, and specifically says about this:

Instances whose admins directly endorse violence¹, systematically look the other way²,
¹ e.g. dbzer0, .nexus
² e.g. blahaj, quokk

I don't know the source behind that though - maybe some people on that instance calling for Luigi-ing anti-trans people, or something like that?