Why is Rufus Unlikable?

I find it quite weird that many people seem to link Rufus's dislikability  to the time period he was raised in. I thought that most people, like I, would point towards Rufus's inconsistent personality to blame for his dislikability. Rufus can prove to be a good person throughout the book at many scenes. He really can be playful, nice, gentle, and trustworthy when he wants to. The problem is he is very inconsistent with staying this likable person. Whenever he doesn't get what he wants, he flares up and totally pushes his concern for others' emotional and/or physical pain aside to ensure that he gets what he wants. Not only does Rufus push aside his concern for others' pain, but he also pushes aside his morals.

This is the main reason I find Rufus dislikable, he doesn't have a moral line within himself that he won't cross. You would expect that since Tom Weylin keeps his word with everybody, including slaves, that Rufus would do the same but he fails to keep his word with Dana and send the letter to Kevin. You would expect that since Rufus is generally nice and playful with the slaves (like Nigel, Sarah, and Carrie) that he wouldn't react the way he did to Sam simply talking to Dana about teaching his younger siblings. You wouldn't expect Rufus to forcibly rape Alice over and over again after he was childhood friends with her. But Rufus does all of this and more. He shows others that he can be a nice and trustworthy guy, and thus we the readers set a higher bar for him (that IS attainable), but he constantly lets us down, almost always because of his selfishness and inconsistent line of morality within himself and NOT because of the time period he lives in.