We always do, and the conservatives say, "No, guns don't kill people, people kill people!" and then the liberals say, "Oh, Okay," and we forget it till the next massacre. It was the same after Tucson, Ft. Hood, and every other loser-with-a-gun event.
Cinamark is one of the theaters that has rules against concealed carry. Had someone other than the gunman been carrying this whole thing may have ended far less tragically.