I've read a couple of his essays, but haven't found them particularly compelling. I think he tries to imagine a forest where there isn't one, and misses the few, very large, trees right in front of him.

I honestly think that's a symptom of problems with the sociological field as a whole. The necessary education is a huge, expensive barrier to entry, and there's a lot of competition for not very many and not very well-paying jobs, so it ends up becoming a rich man's (or woman's) field because only they can afford to play. (Anecdotally, all the sociology grads I met through law school were by far the worst of the "jet-setting" crowd, though you may have had different experiences.)

As a result, oppression becomes a nebulous social force that manifests itself in the problems faced by rich people, rather than something generally perpetuated by rich people. So we have this weird scenario where oppression isn't the state's governor telling you that "your kind" isn't fit to rule yourself, and disbanding your elected government, like happened to (poor and black) Detroit. (Or at least there's no interest in talking about it that way.) And oppression isn't the local chemical company seeing you as subhuman scum and negligently poisoning your water supply, like happened to (poor and white) West Virginia. (Or at least there's no interest in talking about it that way.) Instead, oppression is the supermarket cashier being rude to you -- clearly because she has a biopolitical motive to control you.

It really, really seems like rich people have latched onto a justification for being able to say "I'm oppressed too." It's better than "I have to pay more taxes," but only very slightly.

Which systematic oppression, where? Directed by whom, against whom? In order to do what? Why?

Any discussion of "systematic oppression" that characterizes "systematic oppression" as if it's some kind of cancerous disease that spreads everywhere in homogenous form is going to be flawed from the get-go. The strategies used by the post-Reconstruction American South to keep poor blacks and poor whites at each others' throats are going to be much different from the much softer strategies used by modern Hollywood to make Asian people feel like second-class citizens, and both are going to be much different from the much harder strategies used by the Ottoman Empire to hold occupied Bulgaria.

Acts themselves are value-neutral without that greater context. One group might be on top in one area, and another group in another; a Croat shooting a Serb might be a valiant freedom-fighter on one side of the border and a bloodthirsty oppressor just ten miles away.

Or the rest of the hierarchy might vary; for example, Jews got a much warmer welcome in the American South than they did in the North (because "at least they weren't black") even though the planter class stayed on top. A Jewish person trying to organize a mob to go after an Irishman might be administering well-deserved vigilante justice in one area and keeping the uppity poor down in another.

Oppression might be situation-dependent; a white prisoner calling a black guard a "n*gger" might be an act of defiance in a prison system intended to dehumanize and degrade felons to the point of breaking.

There can even be systems of overlapping oppression; "Tutsis" might oppress "Hutus" by being wealthier and controlling the economy of a country, while "Hutus" might oppress "Tutsis" through democratic power structures and/or by being more numerous and better armed.

The OP, I think, ignores all this in favor of some kind of flowchart hierarchy, where "the minorities" are on the bottom and the more "minority" you are, the more oppressed you are by all areas of society (which of course all act in concert), and the less likely you are to have an "ace up your sleeve." That's a fundamentally flawed way of looking at things.