I don't know the details of all decisions lemmy.world instance admins have made, but it seems to me that the #1 instance will always generate the most animosity because it's far more likely than any other instance to find itself in situations where they're pressed to make decisions by their userbase.
Servers with 20% of the users and 10% of the communities, with only like a dozen 'active' communities will simply hardly ever be in that position and generate no meaningful pushback so they'll always look good by comparison. Additionally, even lemmy.world community mods can generate hostility based on decisions they made despite them having nothing to do with the instance management - and since lemmy.world dominates, you're much more likely to be posting in a lemmy.world community.
There's two factors to this. Lemmy has been slow on developing new features. Eventually people give up despite all the promises. This sort of competition was inevitable, and two - and this cannot be changed - there's a lot of resentment and resistance to using their software for political reasons.