Benjamin Kerstein analyzes Glenn Greenwald; Ron Kampeas looks closely at Philip Weiss. All four are Jews, of course, which makes the entire story faintly weird. The more you follow these things, the stronger the impression that absent the Jewish anti-Zionist brigades, in Israel and beyond, the potency of the anti-Israeli legions would be markedly weaker, at least in Europe and North America.
Kerstein makes the plausible comment that Greenwald's methods are the same used by the Holocaust deniers: if the Jews make a claim it has to be false and discounted. Automatically, since their entire narrative is an evil hoax, and everything they say is part of the evil. Kampeas says the hatred shoveled out by Weiss and his ilk is endangering the lives of journalists in the Muslim world. The first allegation is clearly true; the second I'm not in a position to judge.