"thank Bush and Cheney for ISIS (and, by proxy, this attack)"
"it's all the fault of the immigrants...kick them all out".
In many ways, our reactions to events like this speak loud and clear as to who and what we are as human beings.
I remind myself that it's easy to fall into the trap of revenge, but that never works out well in the end. If one does exact revenge for a horrible act, what's left? Even more dead people to mourn.
Yes, there should be justice. Those that planned this attack need to be held accountable, and to the greatest extent possible, rendered such that they can't execute future attacks. But that's different than revenge. Revenge creates a cycle that becomes self-fulfilling. Revenge is like a candy that you just can't stop eating, until ultimately you get sick.
In the end though, times like this remind me of the advice of Dr. Martin Luther King...
...there's already enough darkness.