I have been running a Mastodon instance since like 2016/17 and this has been quietly happening for the entire time I’ve been on the fediverse. (I can’t check the exact date right now as I’m in the middle of upgrading it.)
Do you want to be in the Anime Girl Who Posts Nazi Memes Fediverse? How about the Queer Furry Fediverse? Or maybe you’d rather be in the Mocking Shitposts Fediverse? Perhaps you want the Everyone Has A Photo Of A Human And Thinks Federating With Facebook’s Activitypub Is Actually A Good Idea Fediverse? Or how about the TERF/Gender-Critical Fediverse? Or the “Standalone” Social Site That Is Actually A Fediverse Instance With Federation Disabled And The Credits Removed In Violation Of The Source License?
Some of these Fediverses will happily talk with others. Some of them will rapidly defederate from others as soon as they encounter a place that clearly belongs to a Fediverse they are incompatible with. Some of them quickly get defederated from the Fediverses they are incompatible with. Some of them look at the #fediblock tag, some to keep aware of places worth pre-emptively blocking to make a chill place to talk, some to look for fellow people who have been cast out of someone else’s chill zones.
Not at all, I am very happy to be able to preemptively keep Terf Fedi and 4Chan Forever Fedi and all those other Fediverse the fuck out of my little corner of Queer Furry Fedi. Throwing everyone into one giant discussion forum and pushing them to fight with each other because that’s what keeps the ad impressions coming is not an experience I care to return to.
Realistically though I can’t be bothered to engage in “fighting about which instance is better to be in” though, I know which one is better for me and if you think that one is a shitty place for you to be then I am pleased to have you stay in whatever place you like as long as you don’t try to make the place I like stop existing or change to fit your desires.