When you ask the LGBT lunatics why sexual dimorphism is not normative, they will point to the existence of intersex people. When you point out that the intersex condition is an abnormality, they will say that the incidence of having green eyes is a statistical abnormality as well, and yet no one considers having green eyes to be a disability. They thereby implicitly make the claim that the standards for physical normality are entirely social constructions.
Hence, blind people do not suffer from blindness, instead they suffer from society's irrational prejudice for sight. I do not suffer from cerebral palsy, instead I suffer from society's irrational prejudice for a fine motor agility, and so on and so forth. Physical normality is not anything that nature prescribes because nature is completely and utterly mindless. Fine. But medical science can't get off the ground without some notion of a natural normative standard for the human body. Otherwise, it becomes just an imposition of arbitrary prejudices. Social constructivism, the ideological puppet master behind most if not all of this LGBT nonsense, is really dangerous lunacy.