Guns and the media-mental illness red herring

The NRA and the Big Gun lobby are making the following fallacious argument right now in opposing restrictions on large magazines and semi-automatic assault weapons:

1) Mental illness, violent TV/movies, video games, etc. are more to blame than guns for gun violence.

2) These "causes" are really hard to address, for a variety of practical and legal-constitutional reasons. 

3) Since we can't do much about these causes, we shouldn't do anything about guns themselves.

This argument is absurd. It is basically saying, "Since we can't control everything, we can control nothing." Wrong. We can control legally the sale of guns and ammo. All Congress has to do is act.

No, change won't happen overnight. But if we stick to our guns (pardon the pun) and stop going back and forth on gun control every 10 years, then eventually we will see results.