I realized that the US has a bottomless tolerance for this kind of violence after Sandy Hook. If the shooting of young children in their elementary school could not motivate change in the US, neither will this.
Everyone points to the deranged shooter & rightly calls them cowards.  No one is more cowardly than the US Government for doing nothing to try to make this type of mass murder less likely.
Hiding behind the 2nd Amendment is absurd.  The writers of the Constitution did not intend or foresee the sad state of gun ownership that exists today.