It used to be that anyone believe in such "gender fluidity" would have been called mentally ill, but that is not politically feasible anymore so gender identity and gender expression are supposed to be subjective experiences based on feeling alone. Sex and gender are no longer synonymous with each other, and gender dysphoria, outlined as a mental illness in the DSM-V, can merely be fixed as long as it doesn't cause mental anguish. If a male were to identify as a woman and experience gender dysphoria, the solution according to today's medical practices is for that individual to self mutilate themselves in order to turn into a woman through gruesome surgical intervention. After that process, the person no longer experiences gender dysphoria and is somehow cured.

Gender fluid people would call themselves "non-binary" but what normal folks would call "mentally unstable."

Normally none of this would have any impact on ordinary functioning societies because we would not indulge in the delusion of these people that think their gender can be fluid, but in fact it's the opposite. You're seeing males being put into female prison systems, being allowed into female locker rooms, or being allowed to compete in women's sports. It's grotesque.