The issue with your example is that black men are not in a position of power in society

Power by demographic association is bullshit. Cletus in the trailer park does not wield societal power because a majority of members of Congress are the same color and sex as he is, because they don't work to protect his sex or color - they work to protect their own economic class and that of their donors/owners.

The trick is that you can't take each demographic axis and declare that there is a hierarchy there where one group is the "oppressor" and thus has power over all members of the other groups who are deemed the "oppressed". And usually the whole point of doing so is to try to fit it into a model of Marxist class conflict, which is only really a passable model for economic class (and accordingly only works for other demographic axis to the degree that they correlate with economic class). There are lots of areas where reality violates the fuck out of said hierarchies, and it leads to either attempts to excuse it or bullshit around it that I like to liken to the epicycles and deferents once used to shoehorn geocentric models of the solar system back into line with observations.

, while men (as a whole) are the dominant gender in society.

Hell, look at criminal justice - for nearly every measure where the system appears to favor white over blacks and you would probably call it racist, it also appears to favor women over men (usually to a similar or larger degree) but you would likely not call it sexist because that violates the hierarchy by putting women over men.

Education is similar, there are studies suggesting that teachers preferentially grade in favor of girls (specifically showing that girls get better grades for similar work but that difference vanishes in standardized testing where the grader cannot consider the sex of the student). Girls outnumber boys in both entering higher education and getting degrees, and have since something like the early 80s - yet we still maintain preferential scholarships and recruitment opportunities for women as opposed to men - usually by just deciding the only fields worth worrying about are the few that remain male dominated.

I'm in a piss-filled trench! The wealthy have the power! Though I am stronger than the average woman, which I acknowledge is a useful trait. Especially for digging trenches with piss seeping into them. Now that's wielding social power.

By what metrics do men dominate society?