As a 2X diagnosed Aspie, I claim 100% bullchit on this claim. Do not mix "crazy" with "autistic." Especially when "autistic" is at such a minimal level.
Whatever happened to "crazy?" Why does everything that any nutball does have to be rationalized, compared to a normally-functioning person? I know a lot of people think "Aspies" aren't "normally functioning," but hey...we all know to look both ways before crossing traffic. We all know how to tie our shoes. We all know that stoves can be hot. We're not stupid.
Stop trying to rationalize "crazy." The kid was crazy, and he shot up a school. There's no sense in banning this, or banning that. No need to impose restrictions. No need to enact dozens of laws that would inevitably be nothing more than vehicles to inject pork projects into the country. If he wouldn't have had access to guns, he'd have brought a sword, or a knife. If not that, he'da concocted a bomb of sorts. Kid was CRAZY. Leave it at that.