Anyone who lets politics determine their diet is a fool. Someone who let politics determine their infant's diet is an evil fool. Here's an article on why a vegan diet isn't good for anyone, let alone for developing children.
It might make sense, from a health perspective, to reduce the intake of red meat and increase the intake of fruits, vegetables, and whole wheat. Naturally, increasing the "nutritional density" of the food one eats makes sense, and veggies are very dense. But, one makes such decisions based on biology and physiology, not on politics.
These "parents" found out the hard way. As the father said, "We're vegetarians; we are against animal cruelty, so why would I be cruel to my son?" How's that for asserting moral equivalence between animals and humans?