They’re defederating smaller entities because the network got consumed by corpos. And abuse, but lots of that comes from big services and they don’t defed those.
It’s tempting to believe the email issue really is some conspiracy to keep the little guy down, but it really is just that a new domain, with low volume, is a strong signal for abuse. That is true with or without trouble from Gmail, Yahoo, etc. If you wrote a machine learning algorithm to find spam, your ML would come to the same conclusion. There’s no obvious solution to that.
Fediverse instances aren’t just providers, they’re communities.
Just like email list serves. Should a listserv block gmail subscriptions? I would again argue not.
This is in essence what FB/Meta is doing, all the time, except it’s not individual spam it’s an algorithmically backed manipulation mechanism using it’s users as tools ^.^
Presumably people using Threads want that. Or they’ll tolerate it.