Among the multitude of insults that float around my world, there's one I always find disturbing and a little mystifying: "Self-hating Jew."
Among religious and ethnic insults, it has no obvious parallels. I've never heard anyone described as a "self-hating Roman Catholic," though many Roman Catholics are harsh judges of their Church. Is there such a thing as a self-hating Chinese? I've known Anglicans who make fun of their Church, but no one denounces them as self-hating Anglicans. Muslims may turn against Islam without being called anything similar.
As a disparaging term, it has an unusual effect. It sounds like the start of an argument, but it's more often the end of one. Those who use it believe that it settles the issue. Once the label is applied, the person using it believes the discussion has ended.
I recommend you read the whole thing. Sadly the author does not seem to give a convincing answer. His suggestion seems to praise Talmudic culture for producing a Jewish tendency to think critically - and ergo critique. This does not though seem to answer the question.