Shitty moderation, which is an issue with the startrek.website instance as a whole. RootBeerGuy provided the gist in a comment below, but the catalyst for the exodus was when the mod deleted a post about Sarah Silverman making out with Tuvok. I mean, it sounds lame, but Risa was supposed to be a shitpost community, with its sole rule being “there are no rules”. It was supposed to be a fun place. It happened a few too many times, so the top posters created the tenforward community here on lemmy.world.

A lot of people followed, and within 48 hours the activity on Risa dropped down to almost nothing. The handful of stuff that is being posted is cringy boomer humor.