Carry or own? Nobody is allowed to walk around with an AR. A .22 revolver could have ended this sooner, that's all I'm sayin.
Wenshu, I dunno bout that man. I think they just choose the path of least resistance. And buying a gun is easier than mixing chemicals. Chemistry is easy. Safe chemistry is harder. But then some nut job making mustard gas isn't gonna worry too much about any sort of safety protocol.