Anyone who claims that ethnic Jews can't be ethnic Germans obviously subscribes to a completely outdated, racist definition of ethnicity. Talk:Germans is full of clearly racist statements by this user, and this is relevant to the behavioural problem.
Example: "A person can choose an identity, like an Italian American can see his main identity as American and not feel Italian in any way, but ethnically he will still be Italian, it's not changeable. It's your genes, where your ancestors came from. I don't see what's your problem just admitting the fact that Jews are a separate ethnicity. Einstein never identified as a German but for a reason a few Germans here insist on having some ownership on him (after trying to kill him and his people)." Hans Adler