Anyone who thinks any one answer IS the answer, is wrong. This stuff happens for a combination of reasons. Be if easy gun access, radical ideology, mental health issues, and a combination of all sorts of things.
It's always easy to blame it on one thing (even if it does play a part into it), but we shouldn't ignore the other issues our nation faces. In order to change things, we need to accept there are multiple issues we need to address, and we need to work together to get it done. Not tear each other apart.