Those are 101 level questions that deserve a hard looking into. And the hammer that fell hard on 177 ought to sound an alarm for anyone actually paying attention.
Assuming that they have a patriotic bone in their body and functioning cells in their brains. And are not playing for the other team.
I believe that your fourth sentence gave you the answer. Your third sentence alluded to it, and your fourth answered it.
Here’s another case where 9 were shot and killed, and in this case - 20 injured. Has Obama called for a ban on motorcycles yet?