I'm not sure that follows at all. The people who were growing up in the 30s were much too young to be decision-makers during WWII (which itself started in the 30s, not the 40s, though Americans don't realize that because they entered the war late). They were barely able, if at all, to even fight in WWII. The people who caused WWII probably came of age around or before WWI. Hitler, for instance, was a low-level soldier during WWI. He wasn't a product of the 30s.