Why does one need a Corvette or a Porsche? You can't legally drive its maximum speed, it can be dangerous in the wrong hands and they cost a fortune to own and feed! But people buy them everyday...You can own what you want in America as long as it's legal and you can afford it...
I can name plenty of people that have used vehicles to kill equally as much if not more people than the most famous "AR" mass murderers. Why are they not legislating to prevent the sale of sports cars? Or better yet, what about those insane bus drivers that are behind the wheel when they kill or injure dozens in bus wrecks...