I’ve dabbled in some of the non-dairy milks, and do particularly like oat. However some of them are just sugar water and protein powder if you do a little digging.
I suppose there’s also concerns about infants being switched to dairy alternatives without consulting a doctor.
Just because in your socio-economic circles, no one is a militant enough vegan to feed a nursing baby Oatly or whatever, doesn't mean people out there don't need some guidance.
I mean there's vegans out there putting their carnivore pets like cats on vegan diets, so you can see someone thinking "hey it's just another milk replacement.. it's healthy!" feeding it to an infant is certainly not a 0.001% edge case.
And since GP said infants, if we're including (human) breast milk as 'dairy' then it probably is reasonable to ask doctor about it - IANA parent either but I think the standard powder or whatever substitutes are still (non-human) dairy products?