Yeah, well, in the US, as with just about everything else, we like freedom to an extreme. Here's 'MORE' is the favorite word, even if it falls under 'Just because you can, doesn't mean you should'. We have a thing called HIPAA that prohibits disseminating information that could be damaging to the pertinent person, even if it would prevent this kind of shyte. There's such stigma surrounding being considered 'mentally imperfect' that nobody wants to step on the toes of those when it fits. If you look at the link I posted, you'll see that most mass shootings occur at the workplace and that hits home pretty hard for me since a guy I grew up with was hunted down and killed by an employee at his business. Drug abuse needs to take center stage for this, too- that was the cause for Pat's killer.
Mental health and illegal access to weapons- it's too easy for them to get their grubby mitts on guns and Congress is too gutless to develop a way to prevent it. They should just let the states do it and when 60% agree on the terms, adopt it as a national policy. That way, they won't be seen as 'anti-gun' by their rabid constituents.
The problem- when someone is motivated, they don't give a rat's ass if something is illegal.