What sort of fallacy, if any, does this argument follow?

What are your thoughts about this: www.reddit.com/r/askphilo. . .

This level of smug pseudo-intellectual idiocy requires a fisking. In order to reduce repetitiveness, it should be noted that there are abnormal cases of non “XX” or “XY” chormosome pairings (e.g. XO, XXY), or of a body developing in utero contra to chomosomes, but those are rare and not indicative of a “social norm” of recognizing that the vast majority of people are indeed women or men, a fact confirmed by not only our entire history as a species, but of practically every other mammalian species in existance.

Further, it will reduce repetitiveness to point out basic biological reality: A “Y” chromosome in lieu of a second “X” chromosome is like a fork in the road that instructs the biological program (i.e. DNA) to develop the body and mind along that of a woman (when no “Y” chromosome is present), or that of a man (when there is a “Y” chromosome). Men and women are physically and physiologically distinct from each other on a clear statistical basis. There is not gradual spectrum. You have two distinct averages with outliers that at the extremes can overlap, like two Gaussian curves. Outside of the previously mentioned biological abnormalities, this holds true, and does so for the vast majority of the population. There is no moral or sociological implications from this statement of biological facts per se.

I feel that there is special pleading here. There are many cases where people are mistaken for trans simply because they don't quite fit the image of how a male/female should be. If gender was so obvious why would this happen to begin with?