Most of the comments seem to be ignoring the two examples in the article of children who were in poor health due to deficient diets.
My guess and hope is that this law is to allow the parents of children in similar circumstances to be held criminally responsible, not that police are going to go around checking what's on your child's plate. I expect these negligent parents have the law on their side right now, hence the proposed law. It reminds me of US states (cough, Idaho) that have laws allowing parents to refuse medication for their children based on religious reasons. Fuck them, I say.
If a parent thinks a vegan diet is good for their children and doesn't ensure they get supplements as necessary and the children become sick, I think it's entirely right to hold the parents criminally responsible.