sukiyakii,

As always, most people (including almost all "let no tragedy go to waste" politicians) who join the chorus for further restrictions on private gun ownership will do so without knowing what laws are already on the books or even if the additional restrictions they fancy would have made any difference in this case.  In addition, it would certainly help their cause if they took the trouble to learn how guns actually work, but since arguably intelligent luminaries such as Hillary Clinton, Diane Feinstein and Michael Bloomberg won't, or can't be bothered to, for over 20 years, it's probably a lost cause.