It's that old security vs liberty debate.
Many people (sheep, mostly) want a secure (or "safe") society, first and foremost. The path of least resistance to a safe society is zero weapons, so that's their default setting. But that's not a free society, and people like me prefer to trade some safety for a bit more liberty.
Mental health complicates that, in the sense that a lot of people truly are disordered and really do benefit from treatment, including drugs. Others don't. I don't expect psychiatrists to be mind-reading supermen and know that in advance, which is why my interim solution is what 10th advocates above: civil defense, taught and reinforced at all levels.
That's not a perfect fix either, but giving the maximum amount of people the option to defend themselves strikes me as the only answer that blends safety with liberty. Plenty of people in mental health treatment are probably able to be perfectly safe with guns, including carry, if they're responding to their treatment properly. But, again, there's never going to be a way to be certain. 100% certainty is what antis think is possible, and it ain't.
Allow me to bring up my communist education again.
We had a civil defense from the first grade all the way to the end of the university. The curriculum covered guns, maintenance of guns, ammo, grenades, defense against chemical and biological weapons, survival skills, laws and regulations, home economics. Every citizen knew how to use rifles, revolvers and grenades. People had guns at home but all ranges were under the paramilitary or military organizations. You could apply for a hunting license, and there were stores which did sell hunting rifles and a hunting gear. All other weapons were not sold but those were given to you if you were a member of a paramilitary organization, people's militia member, policeman or member of the military. There were no shootings! The main reason why there were no shootings were these main 5 reasons:
1. Mental institutions worked.
2. No drugs for general public, not even pain killers. All drugs were classified as chemical weapons and no doctor could get hold of them.
3. Guns were not feared and were present. Potential attacker could never know where weapons may be.
4. Sentences were very high. As a result of that, crime was relatively low. 5-7 years for shoplifting, 10 years for stealing from your work, 30 years or a death sentence for a murder. All prisoners worked 8-10 hours shifts everyday.
5. Borders were closed tight. You could not escape from the inside of the country.
I am not advocating that we should copy communist structure but I believe people here are under the impression that communists were not allowing guns at all. In reality they were all about guns and gun education. That, I believe, is a key!
Our existing education sucks! It sucks because graduates do not know basics. They can't understand how medical insurances work, how investing works, how guns work, how cars work......You name it and they do not know it. They also do not know world geography, world history and their rights. Well, don't you think this is a problem?