Leibler's criticisms of J Street arouse hostility because he denies J Street's pro-Israel nature. For him, because they disagree with his opinions in Israeli politics, they must be like "Jewish communists who supported state sponsored Soviet anti-Semitism". But he conveniently ignores that he sides with only one faction in internal Israeli politics. And he is willing to ignore truth in order to say this- for to say that J Street are trying to undermine the Jewish state is a complete lie. They seek what they believe is best for Israel- just not what he thinks is best for Israel.
Jerusalem light rail conductors striking over new train schedule (Haaretz)
from the article: Response / On 'exorcising' Israel bashers from the Jewish mainstream