Unless i misunderstood, I believe the point of this post wasn’t talking about defederating, it is asking about protecting the users data from Meta if federation happen, and for that point it is what I said, his data is as protected as before, federated or not, Meta won’t get access to any extra data from being federated than it already has access to now.
Defederating is another entire discussion that is really up to the instance admin, self hosting is the only way to really guarantee anything if you want that much deep control of your data and fediverse experience.
I saw this exact popup yesterday, I remember seeing something similar to it before but it has been quite a while. The thing is, this single popup broke my computer entirely, I was playing a game and it jumped in front of the game, immediately stole the games inputs and I couldn’t even pause it. Then clicking don’t switch did absolutely nothing and the popup remained there, and any attempt to forcefully close the popup failed. Also, I was streaming at the time to my tv, and attempting to use any system related screen is blocked (and this popup counts as a system settings screen!), So it just crashed the entire thing while I was trying to dismiss or close it. I was stuck and couldn’t even reboot, had to hold the button and lose any progress I had in the game.
So yeah, I would be very interested in not letting this happen again as well.