Are these apples relevant to an issue affecting oranges?
Why do you think they're unrelated?
Maybe. But to refuse to rent to specific men based on their race? No that is not (or should not be) acceptable.
If you allow refusals for any reason, then someone can always pick an "acceptable" reason and not much you can do about it.
Yes, I am aware I can't actually do anything about this, I was answering a different question.
Would you agree that she shouldn't be forced to rent to a man she felt "uncomfortable" with, even if it was just a feeling? Especially talking about hosts that truly are offering their residence, part-time (i.e. not running a small hotel chain).