I've found that lifelong omnivores tend to be a lot more tolerant of my veganism than ex-vegans. Seriously, what is it with ex-vegans? A lot of them are downright belligerent. I've noticed this trend online (don't think I know anyone who's actually followed this path IRL) where former vegans become followers of Weston A. Price and start praising the virtues of meat and raw milk and stuff. It's kind of like former diehard atheists who become born-again Christians (or vice versa).
Anyway, here's a good article about the science (or lack thereof) behind the WAP theories and the health benefits of soy: