What is a word for hates humanity?

The best definition of someone who dislikes people is a misanthrope. The most simple definition of misanthrope as defined by Dictionary.com is "A hater of humankind". Short and sweet. You can read the rest of the answers below but I think this is your best bet.

If you mean someone who just hates ALL people, the Word is probably 'antisocial' and I'm sure psychiatrists have a few Latin names for this disorder.