I moved from Lemmy.ml because I liked the name of Lemmy.world and it ran a newer Lemmy version which meant I could make communities. I moved from Lemmy.world because they defederated from piracy communities they didn't even host (but for some reason still kept the small piracy community they DID host) From thelemmy.club because I couldn't see the Hackintosh community from there (probably defederated) Now I spent some time looking on join-lemmy.org and checked out some instances and this (lemy.lol) instance seemed good, so I chose that.
The issue is that a community on any platform is made by the average users, not the moderators. If you splinter a community into three competing communities, you will probably severely damage its integrity as a whole. It's similar to the issue that some Discord servers have, where they tell people to take discussion from the main channel into different channels. More often than not, this kills the discussion because few people actually move to a different channel, with most opting to drop the discussion entirely.
A few people shouldn't have complete ownership over something that exists because the people under them make it so.
At the end of the day, it is the moderators who maintain and control the community. They control what users even see, so it's not fair to say a community is made by the average user, the average user is completely silent. I would rather competing communities over every community being at the whim of the masses. The masses are easy to misguide.