"Nothing to do with Islam" -- the parental warmaking version.

I read somewhere this morning, perhaps in the International New York Times, that one of the motivators of Saman Abedi, the Manchester Mass Murderer, may have been... that he witnessed his father in action in Libya, in the fight to overthrow Col. Gaddafi. Violence normalised violence for him. And that's why he killed 22 random young ones.
But... but.... In that case why wasn't there a mass outbreak of terrorism or random murders after WW2? Plenty of kids saw their parents, fathers mostly, waging violence during that war. And plenty more violent than the Libyan skirmishes, I'd wager.
So I'm going to add this excuse to the growing pantheon that makes up the glorious genre -- "Nothing To Do With Islam".