Total happenstance! One of their workshops is right next to mine, and I walked past one morning and spotted a prop I recognised. I poked my head round the door and asked if it was what I thought and between various people being astonished that I had recognised it, they told me they were just starting the build and how to take a little peek. It was only half finished but it was really really cool nonetheless!
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.
It’s a fair point, “meta bad” is poor discourse. The most prevalent concern I’ve seen is that allowing federation to Meta is setting the stage for another Gtalk-XMPP style conflict.
In effect, when a party has such a disproportionate user base, they can use that to dictate terms on the evolution of the protocols that underpin a platform.
Here’s a write up by someone who worked on XMPP and Gtalk who puts it much better than I could. Article