Britain has a knife crime problem that puts American gun crime to shame. People will use anything to try to kill others.
If this means we will do more for mental health in the USA, hey it would be at least more effective than more bureaucratic gun regulation bloat that isn't enforced right half the time anyway because no one can understand it.
But of course guns are easy to blame, people like easy scapegoats. The truth is always more complex than that. Better enforcement of existing regulations and fixing loopholes would do good to stop these kinds of atrocities but so would more funding into mental health, reducing it's stigma or countless other things within our society. If the guy had so many issues and was discharged and all that, background checks should of cleared that up. And if it didn't, I bet it's due to a loophole.