What? I am not a pro-gun person at all, and tend to irritate pro-gun people when I talk to them about guns. I'm even uncomfortable when people I know and trust have them near me. But saying that the majority of gun owners are clearly mentally ill is just nonsense. 

If it's so clear, what is your evidence? Remember, 41% of all US households had at least one gun in them last year. I have a problem believing that 41% of the population is mentally ill in the way you suggest.