High capacity magazines have one purpose. To kill as many humans as possible in a short amount of time.
While the police in Atlanta were responding to one spa shooting, the dude was spraying bullets at another. We were fortunate that even more people weren't killed by the incel/racist/misogynist with a high capacity magazine weapon on his person.
The spread of these weapons has also led to the militarization of the police. Today, old police shows look quaint as the police holster their six shooters.
But eventually, the police forces in America became militarized because they were outgunned on the street.
Mental health and gun ownership should work in one simple way: License guns the way you'd license anything else - prove you are capable of using them. Then, limit what can be bought. Nobody needs a high capacity magazine.
You can better protect your home with a shotgun loaded with buckshot than even an AR-15. The argument that AR-15s and similar weapons are used for home defense is used by men who have never grown up and don't want their toys taken away.