This is from an interview with Michel Foucault in the mid-1970s:
Interviewer: You seem to have kept your distance from Marx and Marxism; this was a reproach that was being addressed to you already about The Archaeology of Knowledge.
Foucault: No doubt. But there is also a sort of game that I play with this. I often quote concepts, texts and phrases from Marx, but without feeling obliged to add the authenticating label of a footnote with a laudatory phrase to accompany the quotation. As long as one does that, one is regarded as someone who knows and reveres Marx, and will be suitably honoured in the so-called Marxist journals. But I quote Marx without saying so, without quotation marks, and because people are incapable of recognising Marx’s texts I am thought to be someone who doesn’t quote Marx. When a physicist writes a work of physics, does he feel it necessary to quote Newton and Einstein? He uses them, but he doesn’t need the quotation marks, the footnote and the eulogistic comment to prove how completely he is being faithful to the master’s thought. And because other physicists know what Einstein did, what he discovered and proved, they can recognise him in what the physicist writes. It is impossible at the present time to write history without using a whole range of concepts directly or in- directly linked to Marx’s thought and situating oneself within a horizon of thought which has been defined and described by Marx. One might even wonder what difference there could ultimately be between being a historian and being a Marxist.
https://monoskop.org/images/5/5d/Foucault_Michel_Power_Knowledge_Selected_Interviews_and_Other_Writings_1972-1977.pdf
To understand the significance of this, you have to understand that Foucault is a major progenitor of critical theory. He was a towering figure who paved the way in the 1960s and 1970s for today’s woke ideology by updating Nietzsche for the age of postmodernism. 100% of critical theorists read Foucault or read critical theorists who are steeped in Foucault. The above quote shows how steeped Foucault was in Marxist dogma.