They are doing something, its just not what you'd probably like. But you cannot say they are doing nothing.
Concealed Carry Reciprocity Act would do away with school gun free zones and allow citizens with concealed carry permits to do so in any state of the Union regardless of the state the permit was issued in. Would this have prevented what happened today if it were already law? I don't know. But claiming the government is doing nothing is objectively false.
It's probably the only effective thing next to banning them entirely. But I ask you, would you rather live in a world where everyone is armed, or no one is?
I would like to live in a world where no one is armed, but that usually ends up with the wrong people being armed. It's more of a "safe than sorry" deal.
How would the bad guys get guns if they're illegal? Wouldn't a complete ban allow the ATF to conduct sting operations on any potential buyers?
You can't uninvent something by making it illegal. The knowledge to make them isn't some closely guarded secret held only by big manufacturers. If there's a market, there will be production.
The man who killed a police commander in Chicago yesterday had an illegal 30 round magazine as well as a defaced, illegal gun.