Young babies need real milk- milk that comes from its own species. Humans are not intended to consume any other milk than the breat milk from other humans. The manufacturers have to put that "disclaimer" on there, because at some point, someone used soy/rice/nut milk to feed it to a very young child/baby (whose nutritional needs cannot be met that way) and when they became ill or whatever, sured the company. It's a protective disclaimer. As far as veganism being "healthy" for children, yes. It is the healthiest, when done armed with the correct information on nutrition. With proper combining, supplementation and suport, it is the healthiest way to raise a child. My 11 year old daughter is vegan and has no illness (not even colds). But I am not basing my statements on my experience alone. I am a Nutritionist and know this to be true because of my education and studies.
"Yes! Live! Life's a banquet and most poor suckers are starving to death!" Auntie Mame