[defilade]

Here's the calculus from the legislator's perspective: regardless of what you pass, no one will know for years if it worked. In that case you might as well do something dramatic that provides you with a big victory lap and a resume item for your next election.

Gun violence is a complex problem with many variables and to really fix it would require a lot of research and carefully structured legislation. Much of it probably wouldn't work the first time either, so there would have to be some experimentation. That's not appealing to most politicians.