A very shrewd post from Greg Sargent. Money quote:
It's true that Obama stated clearly there that rhetoric didn't cause the shooting. But these lines are best understood as a set up to the larger point that followed, which is that the shooting confers a moral obligation upon all of us to improve the tone and integrity of our discourse. If Obama had delivered this latter message in isolation, without the set up, conservatives would have rejected it as political, as criticism directed at them.