A lot of people are struggling and hurting out there. They have no money so they become ostracized by friends and family. No job, no hope. No more house/apt/condo. They don't know where to turn.
The deep emotions that inevitably surface appear irrational and usually come at an inopportune time.
Again, what he did was downright wrong but there's probably more to the story.
Probably the story is that the guy is a loony and should have been placed in an institution years ago.