God may not make "mistakes", but God does make a lot of babies whose anatomical features are either partially or fully mismatched to their genetic make-up, and also makes quite a lot whose genetic make-up is neither XX nor XY. However, there's nothing in this article to suggest that this child falls into either of those categories.
Yes I agree with you. And if there was a genetic/ physical problem I would understand allowing a child to choose which sex he/she most identified with. But as you say this does not seem to be so in this instance. So in my mind the experts and the parents are abusing this child.