Claire Rubin has another website other than her Recovery Diva blog that she moderates, see Disasters and Faith-Based Organizations. One section there is dedicated to Active Shooter and what can be done before such an event happens and then also what people can do during such an event. Things like Run, Hide, Fight.
Then there is this fact — and, I say fact specifically — there are voices in our society who are motivating these types of incidents. What was only once whispered in private, is now being said in public and on mainstream media outlets. The "dog whistle" has now become audible to many. Words do matter and those who foster conspiracy theories are carving out a special place in Hell for themselves. Whether they or those they work for are doing it for fame, recognition or money, they will pay the piper someday.
Here are some examples of the language I'm referring to:
Globalists=Jews
Nationalists=White Nationalists
Any denigration of one race=Mexicans are rapists and murderers
Attribution of evil to a religious faith=All Muslims are extremists
Name calling of particular persons of a race=Low IQ
Criticism of the media=Enemy of the people
Good people on both sides=equates the actions of one group of people
United Nations=Globalists
Shit hole countries=races who make up that country
If everyone who is not of "native born" American heritage would be asked to leave the United States, then all the Indo-Europeans, a.k.a. Aryans, need to be the first ones on the boat out.