Ha, that's funny! And sad, that a doctor doesn't know what veganism is about. Though, veganism would tend to run hand in hand with wicca (or whatever the terminology is) since a major tenets seems to be respect for naturing and living beings. Granted, I know very little about wiccans.
But no, my religion has never been questioned due to my veganism, but my sexuality has. I'm told that eating meat is a requirement for being heterosexual. That explains it.