Now this doen't happen in New Zealand or rural China,Finland,Britain Portugal,Ireland ,Denmark,Czech Republic in fact the only country I know well that does this is USA with numbing regularity, I wonder if ready access to lethal weapons may be the clue ? There are a few gun crimes in France Italy Australia but I doubt the annual toatl would match a normal week in Chicago

http://homicidecenter.org/services/data-sharing/

Cycle

Some lunatic shoots up Diner/Mall /School
Public outrage a few 'radcal' Dems call for more gun control
A week later it's forgotten in the sea of similar crimes
Next Month the next outrage and so on

Darwinianism for slow learners