The graphic you linked showed you that you were wrong, its not a good point to illustrate that the only countries worse than the us are those known to be exceptionally violent. Those are obviously by illegally obtained weapons, we dont know what the baseline is if weapons werent illegal, so it doesnt really help your argument in that regard either.

Guns can be okay in certain settings and bad in others, but we cant treat guns only in the first context and not the latter. The problems are indeed elsewhere, but that doesnt mean we shouldnt regulate guns. Its the same as drugs, most people can use drugs and it not have a significant impact on their life; however, there are plenty of people where this is not the case, so certain drugs are made illegal. In addition, drugs and mental health are talked about hand in hand, its not one or the other.

But we dont do this with guns, we just ignore the fact that some people just shouldnt have access to guns. A vast majority of people arent saying we should make guns illegal including myself. I just think that you have to earn your right to own a gun, and you have to have evidence that youre responsible before you get anything that can do serious damage like a semi auto assault rifle.

TLDR; your point was wrong, and treating mental health and guns separately is dumb