There is an enormous difference in the level of carnage.  The episode in Edmonton caused little harm in comparison to the bloodshed in Las Vegas.  Why?  Because the guy in Vegas had access to no end of weapons and ammunition.

The editorial dumps on Trump, not because he has failed to fix the problem, but because he failed to even mention it as a problem.  At least Obama had the decency to mention that gun control is a problem that leads to episodes like Sandy Hook.