The concept is not difficult to understand. Intersectionality is a currently popular western-left political theory that dockets people onto a hierarchy of victimhood according to ethnicity and/or gender identification.
It is the most popular form of identity politics, today.
It postulates a theory of Good People versus Bad People, which is to say, oppressed versus oppressors.
The Good People, the oppressed, are "people of color" (whatever that means, exactly), the non-white poor, and the gender-disassociated.
The Bad People are "white people," particularly of the masculine variety, "Zionists" and the rich.
That, in a nutshell, is progressive-left ethnic politics in the West today.
But what nobody discusses is the fact that this whole set-up flies directly in the face of Martin Luther King, Jr.'s admonition to judge people according to the content of their character, rather than the color of their skin.