Trying to figure out what exactly they want to ban now? The dude was already breaking a bunch of laws and, as far as we know, didn't have any negative history.
On the whole "mental health" issue, we don't ~ever~ want that kind of draconian power in the hands of the government. This is because what normal people term "mental health" and what government people term "mental health" are two radically different things. Nearly every person in the USA has a mental health history, if you've ever seen a doctor, for any reason, then you have a mental health history. Furthermore many people deal with short term issues like depression, anxiety, insomnia, and various emotional problems as a result of trauma or other major life events. Family members die, you lose your job, have a break up, get a divorce, and so forth. These are all short term issues that are typically resolved in a few months to a year.
No reasonable person will say "your father just died so we are confiscating all your firearms and placing a lifetime ban on your 2nd Amendment rights". Yet that is exactly what the government means, it's happening in California and several liberal states right now. Many of them have mandatory reporting rules that require doctors to report to the state when a patient is in possession of firearms, and the results is the police coming back and confiscating them and the owner needs to pay a lawyer to go fight in front of a judge to get the judge to order them returned. Then when they go to the police department they are told the firearms have already been destroyed.