Hating humanity is like Mac. It's cool while it is the anti-culture, but then when it becomes to standard culture, and Mac becomes the very "man" they defined themselves in opposition to, it stops being cool. Being positive for a time was the anti-culture (see hippies) but then it was overdone, and so for a long time now being a cynical prick who decries the state of humanity while contributing absolutely fuck all to it has been the cool anti-culture, (see HOUSE M.D. and the problem that you are referring to).
The good news is that eventually, hopefully sooner rather than later, hating humanity will be typical, and the rebellious view will be liking them. Just like non-conformity is "totally conformist"...
Either that or someone will look up the definition of hypocrisy, and/or hear the phrase "the pot calling the kettle black".