google added things that only they knew about, which broke the other XMPP apps, driving people to install google talk instead. Sure, eventually people figured their shenanigans out and their apps started working again but the damage was done. Repeat that a few times so that most people were using google talk, then flip the switch and everything that’s not google talk was basically a ghost town. People don’t stick around in ghost towns

you know what I meant. Block them with extreme prejudice when they’re identified

as for your second point, I assume there will be considerable pressure on all instances to follow suit or be defederated themselves. Don’t let their taint spread

how could we disallow them from joining?

easy, identify them, never allow them to federate, block them in your firewall. Their instances won’t be anonymous

this is why the powers that be must never be allowed to join the fediverse: they’ll destroy it

great article, if you’re here scrolling through the comments I urge you to stop and actually read the article, it’s worth your time I promise