I too have read this letter and there are some statements for which I have great sympathy.This paragraph however I found disturbing:

"The signatories are particularly concerned that unfounded accusations of
anti-Semitism deflect attention from Israel's accountability for what many
have called war crimes in Gaza. They state that B'nai Brith and the
Canadian Jewish Congress have led campaigns to silence criticism of Israel
on university campuses, in labor unions and in other groups. Immigration
Minister Jason Kenney and Liberal Leader Michael Ignatieff unquestioningly
echo the views of these particular Jewish organizations."

Is there actual proof for example that any Jewish organization has "led campaigns to silence labour unions?" Besides the usual caterwauling around Sid Ryan what other hard proof do you have of this charge?To me it sounds terribly conspiratorial and hyperbolic without some back-up. The only other thing I would comment on is the style of the "op-ed". As a writer I can note that this is not in an op-ed style. It reads much more like a news release (albeit a rather long news release). Frankly it leaves me cold. A statement with such good beginnings should have been better referenced with appropriate journalistic style.