I think the author tried to read too much into too little. I just read the intro myself, as the author seemed to admit at the beginning that he was stretching a bit.
These kids didn't have enough mental capacity to do much research on anything. They seemed mostly just out of control and mad at the lack of love. They admired Hitler and Manson mostly because it made them noticed. Not from any real understanding.
A better understanding of these guys might be gained from reading Dostoyevsky. From what little I read, "Crime and Punishment" seems to have been written about those two.
