Not every criticism of Israel is Anti-Semitism, but more than enough use it to rationalise their Anti-Semitism.

I agree with this completely. And, conversely, there are more than enough people who use the charge of anti-Semitism (as well as "self-hating Jew", and "not Jewish enough") as a way of trying to stifle legitimate discussion on the subject of Israel, regardless of whether or not the people being so charged are actually anti-Semites. That is what Martin Gibson does.