Why do Jewish people seem to hate messianic Jews so much?

I don't hate them, but they certainly are annoying. Your average Jew is not going to push his/her religion on you. A Messianic Jew will try to get you to believe in Jesus. Now, you cannot be Jewish and believe in Jesus as savior. It is an utter contradiction in terms, like someone who claims to be vegetarian and eats fish. There's just no such thing. The person is lying or delusional.