This action, and the subsequent reaction, tells us less about Obama than it does about liberals. Identity politickers are often the most enthusiastic boosters of donkey-worshipping lesser evilism, and lefties are well-accustomed by now to hearing of our secret bigotry for not doing the greatest deed possible for social justice, voting straight-ticket Democratic. Watching them flail furiously while Obama tosses them over the edge would make a less modest man say "I could've warned you." (Glennzilla, as usual, hits it out of the park.)
Liberals have sat by patiently while Obama mostly appionts a collection of cruise missile liberals, neocon holdovers, and big-business lackeys to man his administration but this, this, is a slight up with which they shall not put. Perhaps, if they had been a little less demure, the situation wouldn't have reached this point. ("First they came for labor, but I said nothing, because all of those working-class people are probably homophobes anyway.")
Ah, there's another point. Liberals are more than happy to play the intellectual totalitarian game when the Big Two are at stake. The treatment of Warren here reminds us that, regardless of how your position on any number of other issues, if you're not on board with the Big Two, then you can sod off. Not only does this do little for achieving any other progressive goal, I really doubt it does anything to hurry the pubilc acceptance of gay and lesbian relationships. Yes, we can wait for older generations to die off and be replaced by younger, more tolerant ones, but that's going to be a mighty slow process. Winning now is going to mean changing the minds of people who presently disagree with you. That's not likely to happen if you're intent on declaring their entire political person anathema and beneath contempt.