I can see why Christianity is so appealing. You can do anything you want and then blame it on God. Of course they refused to bring their kid to a doctor - then it would have been discovered that they weren't feeding her properly and probably would have been reported to CPS, which is precisely what these delightful parents suspected and it's why they didn't go. This wasn't a case of ignorance - they knew they were doing something wrong and chose to not out themselves by just neglecting their child.
And I'll be honest, I don't know what the hell kids that are are supposed to be eating, so I don't know if chicken, apples and cheese are an acceptable diet. But when they say they fed her at 2:30pm one day and she hadn't eaten since then the day after at 10am when she was found dead, that seems like a pretty damn long time for a kid to do without food. Hell, it's a long time for an adult to go without food! Don't you have to feed kids that age every two or three hours? Sure, they fed her, but why didn't they feed her more often? Too poor? They were afraid of her getting "fat" and chose to give her less than she needed? It wouldn't be the first time I've heard of parents barely feeding their kids because they're worried that their infants will get too fat (mind you these people think typical baby fat is too fat).
Nobody's discriminating against him based on his religion, though they might give him hell because he chose to kill his child and then blame it on the Bible. So if there is any discrimination, he brought it on himself. He also chose not to vaccinate his kids because he has a "survival of the fittest" mindset, which is kind of funny because religion and Darwin don't usually play very nice together. But anti-vaccination sure won't be winning him any brownie points, either with the law, his fellow inmates, or his imaginary friend.