You are already being vetted (getting permission) to buy a gun by having to go thru the NICS process. That doesn’t stop a private sale, of course. At this time.
Do we want to stop truly insane people, or not? If we do, then something along these lines is reasonable. I have an uncle who was diagnosed at a young age with schizophrenia. He was, at times, violent. To my knowledge he never had or tried to get a gun. I would not be happy to hear that he did.
The ACLU fought to close down all the insane asylums. What stops the former residents from doing some major harm?
And I know there is no perfect safety in this world. But some things can be done that won’t be more devastating than what we already experience.
It does in Colorado now. Universal background checks on all private sales. No FFL will do the check so any private sale is de facto banned in Colorado. Because of people like you who cannot see the problem with background checks.
Name a mass shooter that did not legally buy a gun after passing NICS. The Sandy hook shooter did not, he killed and stole to get guns. Virginia Tech, Batman Movie, Giffords and a federal judge, all passed one of your SFW background checks.
Background checks are de facto gun bans. They do NOTHING for public safety.
Background checks make progressives feel good. That is all.