lemmit.online is a controversial lemmy server since its sole purpose is to run a bot that mirrors reddit posts to lemmy. Previous discussion 3 years ago about whether to block it: https://lemmy.ca/post/1380644
Currently it is blocked from lemmy.ca and I would like to unblock it to ease weaning off reddit gradually. If I can use lemmy.ca as my main site with links off to reddit on occassion I don’t need to use reddit anymore to browse but just drop in for a specific post of interest.
The main complaint is it can fill up the all category with high volume of low interaction posts. This can be dealt with on a per user basis by blocking either the lemmit.online instance or blocking the bot@lemmit.online user.
Looking at the top 10 lemmy instances on https://fedidb.com/software/lemmy here’s who allows or blocks the lemmit.online instance:
lemmy.world ✅
lemmy.ml ✅
sh.itjust.works ✅
lemmy.dbzer0.com ✅
lemmy.ca ❌
programming.dev ✅
lemmy.zip ✅
lemmy.blahaj.zone ❓
ttrpg.network ✅
lemmy.one ✅

I didn’t know about it until I stumbled across that issue. After playing around with it, it is a possible solution but I think we would need the lemmit admins to make that change in order for it to work.
What I’ve learned:
Since it is a property of the community, trying to override it on our end might lead to federation issues because of the ambiguity.