There is good and bad idpol. Good (Marxist) idpol is simply the recognition that while the proletariat as a whole is alienated and exploited, certain subgroups within the proletariat – women, ethnic/sexual minorities, etc. – are ultra-exploited. It is natural for members of these subgroups to organize on the basis of their identity. This is nothing new, and has always been the modus operandi of communists: see, for instance, women’s organizations in the Soviet Union. The important thing is that there be solidarity between the various groups, and that they be explicitly united by a proletarian interest; this was the basic idea of Fred Hampton’s Rainbow Coalition.

Bad (liberal) idpol ignores the class aspect altogether, and tries to pit various groups against each other. It is thus opportunistic, and a bourgeois infiltration of Marxist tactics. Liberal idpol tends to foster an illusory sense of vertical solidarity: i.e., it tries to convince Jane the working-class single mother that because she and Hilary Clinton are both women, they share a common interest. Obviously this is nonsense, and leads to the “more female camp guards!” mentality that you find so often among liberals.