I have no problem with vegans. I have a major problem with child abuse. Those people can't possibly have not known their baby was starving to death; if it was that small, all they had to do was look at it. Why no parenting classes? Why no postnatal care? A vegan lifestyle isn't cheap; I would guess they could afford it.
I'm a vegetarian, but if I had kids I woudln't force them to be. In fact, I'd probably start eating meat again if I ever adopted, because it would be cheaper and simpler than making a meal for me and then a meal for the kid/kids and my partner. I'd draw the line at keeping food around the house that had instant artery cloggage, but I wouldn't force something so extreme as no meat (let alone no meat, no animal products) on a developing child.