Postmodernism was a reaction to movements like Frankfurt School which is pretty much peak Modern. You can see that in how pretty much the only consistent part of postmodernism is rejecting cognitive structures and abstractions for interpreting society like the example you gave of "reduc[ing] everything to power plays between collectives."
A reaction that builds upon and encapsulates Marxist meta-narratives. Yes in theory postmodernism can point to a diverse set of perspectives but in practice it's homogenous groupthink within a Marxist meta-narrative. End result is people operating in worldviews consisting of moral relativism and variations of "Marxist struggles". It's a worldview that has conflict intrinsic to it.
The rejection of meta-narratives is the underlying theme of postmodernism, and is common throughout it.
I would suggest you dig deeper into these concepts, as you seem to have basic misunderstandings about what they mean.
And there's nothing wrong with safe spaces. You're not owed "logical discourse" on your terms. People sometimes just want to occasionally not be bothered by every bro who thinks that because they've watched a lot of Jordan Peterson videos that they're suddenly on the pinnacle of philosophical thought. It's tiring in a way orthogonal to the validity of any points being made. Additionally safe spaces aren't typically where instruction is held, and, despite the propaganda, not an effective way to avoid topics completely by design.
