In no way have I ever suggested that we can stop this from happening. Not everyone with mental health issues can be helped.I can't do that since I don't know the mental makeup of every single person who has shot someone. If you feel ok with making the assumption that you do know their makeup, then that's ok. I understand why people want to always blame mental illness. It's hard to face the fact that some people in this world are just evil and by saying they have an illness it gives us false hope that we can stop this from happening if we can just get them some help.
I fail to see a distinction between people who are "just evil" and those who are mentally ill enough to slaughter innocents, other than semantics.