A brief read of the tweets included in the article he links to regarding his firing gives me the impression that it's the latter. In fact there is one tweet of

A brief read of the tweets included in the article he links to regarding his firing gives me the impression that it's the latter. In fact there is one tweet of his which references exactly your point about the deliberate confusion of anti-Semitism and legitimate criticism of Israeli policy. Can't say I've looked into it extensively though.