why is this happening?

Another mass shooting today.   This one was at a Wal-Mart.   I can't even imagine what that was like.   I hope I never find out. 

I wish I understood what drives the people who actually flip out and bring a gun to the movies or school or Wal-Mart.  Are they protesting something?  Are they hypnotized?  

I recall a time in my life that nearly all killings were committed by people who knew their victim.   Bombings happened,  but not very often,  and they were for a reason ... and terrible. 

What is the motivating factor for these nearly daily mass shootings?

What do they want?