I'm going to start a new club: FETA - Fixies Eating Tasty Animals. We'll sit around eating burgers and drinking thick microbrews.
There is no correlation between riding a bike with no gears and diet. Everyone has different ethics and dietary requirements (I greatly admire true veggies and vegans for their discipline; my body has other requirements). If the kids going vegan and drinking PBR think that's a fixie thing, they need to go to the Gap and buy a new identity.