we can't just say 'all humans are automatically in'.

We can. Humanity and personhood can be distinct. We can just say that. For instance a brain-dead human is still a human despite lacking all self-awareness and intelligence. That's fine.

Not trying to be rude, but I'm not even sure what your point is. Denying a bigot's humanity because a cuttlefish is a person... You're making a connection somewhere that I'm just not getting.

I'm saying someone is a human being regardless of their intelligence or compassion. I think you may be going by Frank Herbert's or another's définition.

EDIT oh I just saw the last paragraph. I see now. I don't disagree that fascists are lacking in certain critical faculties or even that defending your rights with violence is wrong, but I do think it's dangerous to de-humanise others to the degree you're doing.

For one, I don't think humans who lack empathy, etc are P Zombies or anything, so they are capable of experiencing complex pain and distress. They're not things.

Secondly, they can sometimes change and "become" human through experiences. Like what about the hardcore fascist 17 year old, who already had the seeds of doubt germinating in their subconscious? Undoubtedly still dangerous, but very much a full human.