No, because being a vegan is a conscious choice. I would not call someone who does not understand the concepts of veganism or alternatives to be any sort of vegan, much as I would not consider a child indoctrinated into Christianity to "really" be a Christian until they make up their mind for real.
There someone goes again to ruin a perfectly good joke with logic and reason. tee hee hee. But technically, physically is the baby of vegan if they're consuming their mothers breast milk?
I'm wondering are you comparing veganism to a religion? That's actually a serious question.
So if a person eats only roots and leafs because there is no meat nearby, then they aren't a vegan because they didn't have a choice?
Maybe a vegan in practice only?