We don’t capitalize “human” because as of now there are no other intelligent species we have relationships with on that level; there’s no need to add that level of “respect” to the word. But if we did make first contact with an intelligent alien species, I wouldn’t be surprised if cultural conventions like whether or not to capitalize the names of sentient species became a thing.
We don’t capitalise “human”, though. Treating them as equals would be not capitalising it
We don’t capitalize “human” because as of now there are no other intelligent species we have relationships with on that level; there’s no need to add that level of “respect” to the word. But if we did make first contact with an intelligent alien species, I wouldn’t be surprised if cultural conventions like whether or not to capitalize the names of sentient species became a thing.