Allowing an org to federate is not being lenient, it is how federation works. Defederating should be done to protect the federation from a node causing harm to the federation–not preemptively in my opinion.
So let a known criminal into your home, until they commit a crime? Wouldn’t not letting the known criminal into your home be the safer, more protective route?
I think a house isn’t the best comparison here, as a house isn’t a public space, whereas the Fediverse is. A better comparison might be a town square or a park. Anyone is welcome to be there, but if they do something bad, or it becomes obvious that they are going to do something bad, then they can be removed from that space. Otherwise they should be allowed to exist in that space.
Facebook will cause harm by its very presence.
In any event, people with your opinion may end up in one fediverse “neighborhood,” and people with my opinion will end up in another.
I’m fine with that, as the “neighborhood” I end up in will have a lot less inane garbage everywhere.