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).