Global Ethics, Stupid Vegans

I've been reading a little into Animal Ethics, and of course Peter Singer is one of the seminal recent thinkers here. Regardless of whether one finds his ethical theory compelling - here is one easily understandable essay that doesn't - this article of Singer's in New Internationalist impressed me with its clarity on global responsibility.

Somewhere along the way, I bumped into this very sad story of a vegan couple recently convicted for the murder of their baby. It does not prove veganism is bad, only that stupidity is. However, according to this article, while a vegan diet can be ok for adults, it is not adequate for infants.