This is the end result of what I call the dark forest hypothesis of social networks or federated chat services that face similar issues.
Yes, you can frame it in a positive way, like the author does, but ultimately it is about hiding away from bad actors.
Personally, I think the lowest hanging fruit is open-registration servers, that like the article describes are a vector for abuse. That issue should really be solved first before discussing more closed off allow-list only networks.