It's honestly kind of irrational. The "embrace, extend, extinguish" stuff is on shaky grounds as a framework as it is, but it wasn't even part of the conversation until people started trying to retroactively justify the knee-jerk rejection to Meta.
So it's mostly "we should grow the "fediverse" into the new universal social tool. No, not like that".
But hey, here we are. I'm on the record saying that I'll mvoe instances if they join to keep them available.