This happens as a society disintegrates. It is a sign that the point of no return has been reached. We either fall apart completely or that Man on Horseback rides in to become Emperor or Dictator and we do a Napoleon thing. Big War is the end of this, one way or another.
.....Rather this is a sign that a society needs to be cleaned up.
This is happening because the media and our “Dear Leader” our promoting it by giving it so much attention.
It is called the “Copycat Effect” and it is well known.
http://gunwatch.blogspot.com/2015/08/virginia-journalist-shooting-media.html