Trying to follow the purported logic of Barack Obama is rarely an easy proposition, but I think I've got this one worked out. As he sees it, your duty as a U.S. senator is to take advantage of the high emotion of the moment to decimate the Second Amendment, regardless of whether the gun-grabbing, Constitution-shredding move you make would have done anything to stop the shooting that's provided the convenient pretense for your legislative recklessness.
And if you don't do this, you're a coward, and he'll make sure everyone knows it by saying so