I say what I am about to say with due respect as I am deeply engrained with a 1% club here in Toronto Ontario Canada, so the " outlaw " MC culture didn't start after WW2 that is just when the H.A. began their growth with " the big red machine" campaign and the MC culture became more popular when yes more brothers came back from WW2 which also sprouted other MC's like the Mongols out of defiance to the HA . MC's, but outlaw club culture actually began in the early 30's with the motorcycle drag racing scene with clubs like the Galloping Goose and Booze Fighters, then in 1937 in Hollister California (which is where I happened to stay when I attended Monterey Car Week 2 weeks ago) is when the infamous " 1%er " diamond was founded when a motorcycle rally got outta hand in downtown Hollister which I visited to pay respects and the Amercian motorcycle association stated that " 99% of motorcycle riders are law abiding, its the 1% that are not " hence the adoption of the 1% diamond patch by clubs