the strict binary is a world view, not science. scientifically, biological sex in humans follows a bimodal distribution with few but not zero data points between the two modes. and these are not just one single third data point but a number of them.

forcibly assigning those to one of the two modes is unscientific and based of a binary world view.

which is why some nations allow to put "diverse" as sex at birth, or do away with that at all.