Remember when we used to call multiple personality disorder a form of schizophrenia? Today's leftists believe 'multiple identity therapy' is healthy to the soul of the individual and to the body politic.
Age, gender, race and even ethnicity aren't "identities" anyhow; they're simply accidental traits. To suggest that all women, or all blacks, or all Christians have a shared "identity" is ridiculous. Identity is linked not to one's random traits which one did nothing to acquire, but rather identity is bound up with one's person-hood; their defining individual qualities (rightly understood). Identity is not what makes one the same as one's fellows, it's what makes one unique; identity is their differentiating characteristics.
People might share a reverence to an inherited culture or a national heritage, and while it's true that most people are merely the products of their culture and live like bats in twilight; picking up the reflections and refractions of the philosophies which dominate their milieu, that's still far more identifiable than lumping in everyone according to merely their accidental traits and pitting them against those who have different accidental traits.
But atomising and fragmenting people through identity politics so that you can reduce them all to some shared trait is to negate, nay abolish, the individual. Identity politics reduces the overall power of each individual by bribing them with the short-lived power of the mob by turning their particular individual status into merely a class or shared trait. It's simple totemism turned politically into a zero-sum game. (e.g. I am a Buckeye, so I must oppose all Badgers, Gophers, Skunkbears, Wildcats, Hoosiers, Hawkeyes, Spartans, Boilermakers, and Cornhuskers, because their gain is my loss).
The motive of those who play identity politics is to simply amass power for themselves. They seize it by dividing people into groups, imposing and enforcing narrow and rigid group think, destroying those guilty of thought crimes (ironically turning them into an "nonperson"), and offering therapeutic alienation and righteous indignation to assuage the feelings of failure or inferiority of the members of the group, and to teach them to see themselves not as a unique individual with particular qualities and unique potentiality, but as merely an identical irrevocable member of a group of oppressed victims; an atomised particle in a faction, more or less at war with all the other groups. They are reduced to just a grain of sand in a desert at war with the sea and the mountains.
Our enemies won't have to worry about us conquering them, we are dividing and conquering ourselves.