I usually experience this in the other direction, as toot.cat rather aggressively defederates other servers.

It's sufficiently well administered that I'm not aware of any instances defederating it. Where I'm aware of instances being widely defederated, it's almost always been gross abuse and failure of admins to respond in an appropriate or timely manner. I'd left one such instance on account of just such a failure. (Several others shut down, another not-uncommon occurrence.)

Profile migration still has many failings, but it does make moving to and establishing connections from a new instance pretty painless. Losing your old history is a bit of a drag.