This is the best sort of sense I can make of it: The act or result of individual oppression per se is unimportant except insofar as it identifies oppressors. And these oppressors exist as a group, rather than individuals, and thus allow one to categorise according to apparently rigid caste structures in society and across the globe. Which is why the raging lefties (their term) of my uni have arguments over whether gay white men are oppressors of straight white women - the question is, which group is privileged, and thus an oppressive group? Oppressive groups are not allowed to impose upon oppressed groups, because this is oppression and oppression is the bad. So if an able bodied straight white male (of a colonial nation - though this is generally assumed in "white") is trying to impose about anyone else, they are inherently oppressive, and therefore need to be opposed. An able bodied gay white male (I think the consensus was that this is the second most oppressive group) can impose upon straight white males, but nobody else. And so on. So the people championing a cause is a massive part of what determines its justness; one cannot analyse a cause in itself.

And in some sense I can understand where this analysis comes from. It comes from legitimate work looking at the danger of injustice when those who have more power for no legitimate reason impose upon those who do not. But when it's the only mode of analysis you recognise, you get to places where you oppose attempts to stop FGM because it's "colonialism".

I'll emphasise at this point that I'm trying to make sense of the views of uni acquaintances. How widespread this sort of thought is I don't know.