Class reductionism is fundamentally un-Marxist. Here's why: Marx's dialectical method holds that one aspect of society can only be understood in terms of its relations with other aspects of society and that these relations are themselves part of what these aspects are.

The consequence of this is that you cannot actually understand economic class from a Marxist point of view unless you understand it in terms of its relations with other structures of oppression like patriarchy, racism, homophobia, transphobia, ableism etc and vice versa.

Crucially, these other structures of oppression cannot be reduced to class not only because they have their own dynamics and histories but also because class is itself constituted by its relations with them and they are constituted by their relations with class.

Systems of oppression therefore form an interlocking totality of distinct interrelated social structures which is greater than the sum of its parts. You cannot simply analyze class, patriarchy, racism etc as separate entities in isolation and then combine them together.

You have to instead develop a model of systems of oppression which is built from the ground up to understand how different systems of oppression are constituted through their relations with one another. In other words, good Marxism has to be intersectional or it isn't dialectical

This thread is indebted to @RPlateaus who first explained dialectics to me and will be making videos on it in the future and Bertell Ollman's book dance of the dialectic, which you should all read. https://www.youtube.com/channel/UCsln1E-ttrNPsMivrnf9V7w