So Ron, what you`re saying is that since this guy was a US citizen, all we need to do is to stop him from leaving the country to gain any exposure, eliminate all members of a particular belief presently in the country (no mosques or places to gather), stop any "outsiders" from entering the country that have been exposed to that belief, shut the Internet and television stations down so we can`t see any problems in the outside world and eliminate all firearms? I`m following you now, you`re a genius. Ron for POTUS.
Though this is a bit extreme, it`s kind of the same thing, it`s the snowballing effect. Start with one type of gun, then the next, then the next. When you start eliminating anything that is potentially dangerous, there isn`t much left.