In my years of business travel, I;ve spent quite a bit of time in Asia. One thing I learned was that even with out guns, murders and seriel killings take place as they do here. Hammers, knives, saws. If a nut is wanting, they will find a way,
He could have walked up with a Propane Tank rigged with a fuse and killed dozens.
He could have used a sword, as a nut did here in a CA Grocery Store killing and wounding half a dozen people.
Human ingenuity being what it is creates scenarios like 9/11, where 19 Jihadists killed 3,000 people and cost the economy Two Trillion Dollars in one fell swoop.
Those guys had a better kill ratio than the nut in AZ, but the Obama Administration is worried about offending Muslims by calling them Jihadist Terrorists.