What you seem to be against is forcing you to have only one login. That does go against the model we are talking about.

And it isn’t what’s being suggested.

Yes - that isn’t what’s being suggested. And that’s entirely irrelevant.

The correct way to measure the threat a proposal poses isn’t by what’s specifically being proposed, but by what the proposal, if enacted, carries with it - what it necessitates, implies or even just allows.

As I mentioned before, and this seems to me to be the biggest potential threat vector, unless people host their identities on their own hardware, that information is going to be on someone else’s hardware. And that’s not going to be a charity - it’s going to be a business, that’s going to profit off of it somehow. If this proposal goes through and is relatively widely adopted, there will one day be an industry leader in the identity-hosting business, and that company will have leverage over the fediverse as a whole. And at that point it would be easy enough for them to, for instance, strike a deal with the biggest instances so that the instances, in the name of security or convenience or whatever might suffice, only accept registrations through that particular service.

I’m not saying that that will happen - only that it could. And that’s enough, in my estimation, to make it a bad idea, because if the history of the internet has shown us anything, it’s that if there’s a way for someone to control something and profit off of it, someone will control it and profit off of it, and the original proposal that made that possible doesn’t mean a damned thing.