Can someone explain why so many people here are FOR blocking Threads.net on a server level?

I might not be understanding something about the fediverse, but isn't this like if you couldn't send or receive email from a friend because you use gmail Google decided to block @icloud domains?

Like, you're not forced to follow or interact with it, and are free to block it if you can think of a reason to, I just don't see why such an open platform used to limit users in this way