The other side is that the American culture has a toxic side which can drive lonely young men to perform despicable acts.
Imagine being a lonely young boy, growing up getting bullied all the time, being told you amount to nothing, and it's your fault, and at the same time, while everyone around you is deep into corruption and sin, they preach to you that you should be sinless and pure!
I am not American, but I can sense the contradiction from miles away. And if it goes on for too long, especially when one is young, it can turn a person into a mass murderer.
Sadly, mental health issues stemming from society's ills is not really discussed anywhere and in depth. The focus is only on gun laws, gun ownership and gun availability. I am not saying that it is not an important aspect of the problem, but it cannot really be solved by just stricter gun control...even if guns were not really available, the people with mental health issues would use bombs or use other means to kill. But then the focus would be on terrorism, and the mental health problem will still not be discussed, because it's such a difficult topic...