Framing your argument in terms of "fat people" weakens it considerably. There are plenty of lazy skinny people too, and the biggest problem is people's sense of entitlement. Pitting pedestrian/cyclist entitlement against driver entitlement is IMO less effective than treating transportation as a matter for sharing and cooperation instead of competition. As competition, non-drivers will always lose. And no, I don't think that's right, but the universe doesn't care what either of us thinks is right.