Except kids can't be raised on a vegan diet, particularly young kids.

Yes they can: "regarded as appropriate for all stages of the life by the American Academy of Nutrition and Dietetics"(in the context of veganism).

source - https://en.wikipedia.org/wiki/Veganism

I've seen kids on a vegan diet and they aren't nearly as healthy or strong as kids who eat a non-vegan diet.

Well I'm convinced, too bad we wasted all that money on science.