I'm not sure I agree with everything in this Stoller post, but I think it's important to understand that it seems that many on "the left" have internalized the right wing talking point about Move On being a bunch of "left wing extremists" in some sense, and therefore expect them to be the standard bearer for the "far left." These terms are unhelpful and I don't mean any of them in a pejorative sense, but I've long been fascinated by how easy it was to try to portray the very mainstream generally and very "sensible" Move On as a bunch of insane Stalinists (okay, insane Stalinists is probably pejorative).
Whether you think it's a good or a bad thing, or whether you agree or disagree with them on issues and strategies, the fact is that Move On has never been particularly "left."