Children have no sense of the implications of what they say. They just say whatever is on their minds. We train them to be little observers, and then we get flustered when they make observations. And what kids think makes adults squirm. Well I thought my hair was rather attractive gray-brown color, but he was absolutely right.
Children often report what they see, and what they see are differences in appearances.
In fact overweight people are commonly the targets of children's inquisitions. She certainly stopped talking about God. Even harder to deal with are remarks that make children sound like miniature racists. If you put your mind in a teaching mode it may help you feel better about your own embarrassment. Really listen to what the child is saying.