Why Can't We All Just Get Along?

Goldblog reader Jason Snyder asks an interesting question:

Before asking J Street (or its supporters) to stop referring to it as the "pro-peace lobby," perhaps AIPAC should stop referring to itself as "America's Pro-Israel Lobby." After all, everyone thinks that their organization is the most "pro-Israel."

But I'd like to ask a larger question -- why does there have to be such acrimony between J Street and AIPAC? AIPAC's supporters, in particular, seem especially offended by J Street and what it stands for. Isn't there room for diversity of opinion on questions where clearly no one has the correct answer yet? I understand the concern that some of those who support J Street do so for, perhaps, less than staunchly pro-Israel reasons, but is there really no room on the spectrum of opinion for those who think the settlements are an obstacle to peace or that Likud does not have all the answers?