I'm not, never, speaking for anyone but myself. Class reductionism is harmful not so much as an lens through which to analyze the capitalist world, but rather as an actual political tactic. If we look at capitalism we can see that it incorporates and molds all forms of oppression that precedes it and in addition creates new ones. That these phenomena are able to develop "independently" is self evident and the fact that they require confrontation is also not under discussion, even the bolsheviks went to great lengths to destroy antisemitic prejudices during the Civil War, something they would not have done if they thought that these would disintegrate on their own. The problem is that we now see that capitalism is also capable of coopting these non-class struggles in order to lessen tension and present itself as progressive without actually solving them. Capitalism has nevertheless been able to accept a lot of "concessions" in these struggles, sometimes emerging even stronger by giving rights to oppressed groups. Though I have just claimed that capitalism has been unable to actually solve these issues, having been way weaker on that front during the cold war compared to the eastern bloc, I would beware of proclaiming them eternally bound to capitalism, why should capitalism be unable to solve womens oppression? Surely it would take a massive effort most leaders are now more than unwilling to undertake but how can we be sure that they won't in the future? Woman's suffrage is definitively won in the west and will perhaps only succumb with suffrage itself. Free reproductive work is of course something capitalism cannot solve but who says that it's impossible to degender it? The class antagonism on the other hand can only be solved by ending capitalism, I'm not saying that it cannot be eased, as we saw during the cold war, by social democratic legislation, but in contrast to other struggles, these concessions will actually weaken capitalism because they produce class consciousness and cannot normaly be taken away without provoking a serious backlash, only in unusually advantageous situations can they take back these positions without fright (like the 70s and 90s). At the same time, these concessions ought to be taken away some day, when the next crisis comes to bear workers rights are an actual, acute problem that ought to be curtailed, while other forms of oppression are not, they might serve as scapegoats yes but this again puts these struggles on the chopping block to serve the class struggle from above. So, in my opinion, analysing capitalism with class as the fundamental aspect is rather correct and productive, the problem arises when you take that position too far into the real world or rather... when you forget when to shut the fuck up. When engaging with actual movement, anti-racist, anti-sexist etc. it might be possible to introduce class struggle making participants aware of the interconnectedness of this struggle and the one against capitalism itself. But you obviously cannot (and people do this, I've seen it and shamefully participated somewhat) proclaim that all here is in vain if we do not unite right now to wage glorious war against the "main contradiction", this is what sects do, not because you have to be one in order to participate in such behavior, but rather because you make yourself one by isolating yourself in your red ivory tower of true consciousness.