Nothing to do with gun ubiquity, no, not at all

He had a gun. So he used it to kill people he didn't like. That's what guns are for. He used it exactly as it was designed and built to be used.

Meanwhile, in Kentucky, a student shoots himself with a gun he brought to school in his pocket, and the response of school officials is to install a metal detector.  And expel the student. Missing the point completely.

Pride of the NRA, all of them.