It would settle some questions over it if we could simply read the statute or regulation that requires it. So far there's been a lot of hand waving in the press over it and nobody can quote it.
Goes to the incident being a mental health issue more than a gun issue. Where is it specified in Code that the shooter wasn't supposed to be able to buy a gun? And, frankly, what difference does it make now? Crims gonna crim, laws only affect the law abiding. In this case even if there was clear language it didn't do one bit of good.
Now, think about that the next time you are pulled over speeding. You saw the sign, you know there is enforcement, yet you still got caught. All the regulatory language and posted signs did nothing. You pressed the pedal down, you evil speeder, ignoring the law and the safety of the public around you. How about three tickets and you bike to work? We can't even get drunks to stop driving, what do we do, cut off their right foot?
Blaming a lack of thru put to stop the shooter from buying a firearm is playing along with the anti gunners. They want to regulate the process so intimately that you will be required to show a certificate of mental stability to purchase one. As long as they avoid jumping onto that band wagon we are better off.
The real problem is a society which incubates a hostile mind to ethical values. We've come a long way since the Supreme Court was packed with liberal politicians who decided God was dead and we couldn't teach our children morals in the schools we were paying for. Look who started this and who's complaining now?