To speak about the “working class” as a monolith is to ignore the progress made in theories of intersectionality.
Marxists were developing frameworks to understand the unique struggles of women, oppressed nationalities, etc. long before the advent of intersectional theory. It has frequently been insufficient, sure, but your statement gives the impression that the whole domestic socialist movement was hopelessly class reductionist until intersectionality came around, which just isn’t true… at all.
Just to give a few examples: the pro-China Marxist-Leninists—who later became known as Maoists—have had an analysis of “contradictions among the people” since the 60s, which led them to try to win support among the white working class for black liberation during the turn of the 70s. There are relatively prominent communist trends which have held for eighty years that black people constitute a nation, and would be justified to struggle for territorial independence from the United States. There have been Marxist analyses of patriarchy predating the Russian Revolution (1917), which at the very least recognized that women proletarians have different needs and particularities to their struggles than their male counterparts.
So allow me to pose the question: who actually speaks of the U.S. working class as a monolith, other than high school-age internet Marxists?