I think the issue most are concerned with sits under the layer Admins are at. It’s not necessarily about the community administration, it’s about the software that makes up Lemmy. Threads will almost instantly make up 99% of users, so what incentive have they to play nice. The XMPP debacle wasn’t about integrating poorly, it was about specifically building a community in which was dependent on Gtalk users then mutating the protocol, eventually breaking with it. XMPP of course survived, but it died soon after, because when all the users no longer have access to their communities, why will they stay? Lemmy admins are worried that threads will become so integral to the fediverse that it’s removal will mean that users (who let’s be honest, don’t want to check more things than they need to) will go with threads.