Academics took the methods of literary analysis (where you might examine a book through a Freudian lens for example, even if you don't accept Freud's theories as correct, as they may have influenced the thinking of writers who were his contemporaries or grew up when they were popular) and started applying them to the real world without regard for whether the theoretical framework or conclusions had any relation to the real world. Using some bullshit theory to analyze fiction is unlikely to be harmful, because the worst outcomes might be offending the author with the stupidity of your analysis or leading some dumb English teachers to teach that analysis as if it were gospel.

They work entirely in a conceptual framework so abstracted from the real world that it no longer has any meaningful correspondence to reality, and instead of recognizing that this is a form of mental masturbation that could be enlightening or dumbening (yeah it's not a real word, but it works) depending on the particulars, they adopt these frameworks as religious dogma and cram the real world to fit into it, even if it requires bastardizing other cultures they claim to respect and exhibiting blatant racism in the assumption that the various peoples of the world couldn't recognize the characteristics and relevance of the two categories of reproductive capabilities AKA sexes until Europeans came and told them.

They cite rare medical disorders as evidence of some third sex, when actually no one has both reproductive capabilities or some third distinct reproductive capability, even when they are born with mixed sex characteristics, they either have the reproductive functioning of one sex or no reproductive functioning. They cite categories various cultures have for people who don't adhere to the rigid sex roles prescribed for their sex as if this is equivalent to the modern gender dogma that you are what you feel you are.

Even mathematics, an inherently logical discipline, has branches that are so abstracted that they do not apply to the real physical world as we know it. Take the Banach-Tarski paradox from set-theoretic geometry. The idea you can decompose a ball into a finite number of disjoint subsets and recompose into two identical copies of the original is based on certain axioms which don't necessarily apply to physical finite objects as we know them.

What these whackaloon academics are doing is the equivalent of someone citing the Banach-Tarski theorem and using that to assert that you can cut up a real orange into pieces and rearrange to get two copies of the original orange. Except if a mathematician tried that, they'd be ostracized and probably fired and put into a mental hospital.