...only a writer on the level of a Farley Mowat would have you believe fascism was the only reason they signed up. They may have been informed but Herman Wouk aside, how many were dedicated enough to say they truly cared about the beliefs enough to put all other considerations aside.
Which isn't to suggest they weren't idealists or that you had to be a mercenary fighting in something like the Spanish Civil War to be considered pure of heart. Having read through some interviews in our regimental archives, I get the impression that very few guys joined up just to escape the Depression (a common myth) and quite a lot really did want to do something about things in Europe or help the "old country" in a time of need. But that was only a part of it, and it was mixed in with personal reasons - testing or proving one's self, staying with friends, adventure, travel, the usual "old lies."
I guess what I'm trying to say is that it was a complex situation for every individual, and a lot of the rationale for why they did what they did was actually recorded for posterity after the war. They didn't capture their feelings well on their attestation papers, and if anyone did go around to stop to examine the reasons why, I think the Army would have put a firm halt to that sort of thing as counter-productive! A true picture of motivations is something elusive, but of course, understanding why the Germans were doing what they were doing is even moreso.
I don't doubt that figuring out now centuries later what possessed the soldier of 1812 or 1775 to sign on the dotted line or make an X would be equally complex. I also wouldn't be inclined to dismiss it as BS, or if I did, I would be forced to admit that we're still doing the same things. It's part of the game.