Because these anarchist morons are simply eaten up with hatred - they HATE everything and everyone - including themselves.
There is an exchange between Wyatt Earp (Kurt Russell) and Doc Holliday (Val Kilmer) in the movie Tombstone that sums them up pretty well in my opinion ...
Wyatt Earp: What makes a man like Ringo, Doc? What makes him do the things he does?
Doc Holliday: A man like Ringo has got a great big hole, right in the middle of him. He can never kill enough, or steal enough, or inflict enough pain to ever fill it.
Wyatt Earp: What does he need?
Doc Holliday: Revenge.
Wyatt Earp: For what?
Doc Holliday: Bein' born.

The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted. ~ D.H. Lawrence