Why are people so concerned with binary gender?

People are so concerned with binary gender because they have been so surrounded by it for their entire lives that it almost completely defines who they are.

because of the way they think, their culture, and values, many people are unfamiliar with the smallest degree of gender-nonconformity (according to their concepts of the binary genders.) they may not understand someone’s “motivation” to be different, and out of egocentrism (typically cultural and religious) may be disturbed and feel an urge to correct their disturbance by changing others’ behavior. some people have a belief system that catastrophizes gender non-conformity using a slippery slope of conclusions that lead to the extinction of humanity over someone’s favorite color, and feel that it is their duty to force people to adhere to their idea of good in order to save humanity. i don’t think that, but that’s my understanding from debates over gender.