It's been the basis of every concealed and open carry argument for the last couple of decades.
And yet, in this case, nothing. No impassioned appeals for loosening the gun laws so that ordinary Americans could go to the store in the evening to buy some candy and an iced tea without getting stalked and shot by some unhinged vigilante. No solemn op-eds about the dangers for average Americans when venturing unarmed into the streets of their own neighborhoods. No fiery speeches from Wayne LaPierre insisting that if only everyone in the neighborhood had been armed with submachine guns they could have run outside and started firing immediately upon hearing the screams for help. Nada. Why do you suppose that is?
Update: Last night I saw Zimmerman's friend on CNN defending him in a very revealing way: