I find it interesting that your boyfriend hates your parents and yet they don't mind him. This tells me that whatever the problem is, it's your boyfriend's fault. See, if your parents had done something awful to him then that would indicate that they don't like him either but you say that's not the case. It's pretty impressive that your parents are able to be cool despite his feelings, because I'm sure they know what he thinks. They may act clueless, but parents usually notice these things, especially when it involves a guy who's seeing their daughter!

Have you tried talking to your boyfriend about his behavior? Tell him that you would like him to make an effort to get along with your parents. He is acting like a spoiled child and he can't keep this up for ever. One of the things everyone learns as they grow up is that, very often you have to be pleasant to people you don't like. This is how things go in a civilized society.