Denis, Denis, Denis,
If you only read stuff from the MoveOn Web site, you're going to hear only what you MoveOn wants to place in your pliant mind. But I suspect that you are comforted by the notions pushed by MoveOn; notions that place the blame for all our ills on distant boogeymen.
Outside of MoveOn, however, I think you'll find that the accepted, factual reason for lack of a tax "compromise": Boehner went beyond his comfort zone to make a deal. But at the last minute, Reid, on orders from The Big O, demanded an additional $1 trillion of tax increases. Boehner knew that wasn't going to pass the House, so he discontinued talks.
You may still blame the Repubs for the failure if you wish. But you missed the motives by a wide berth.