From wikipedia: "I shall call an apparatus literally anything that has in some way the capacity to capture, orient, determine, intercept, model, control, or secure the gestures, behaviors, opinions, or discourses of living beings."
I mean in many ways people using post-modernism as a foundation for their "Theory" sort of make his point about discipline and punishment. I think his ideas there are pretty straight on and prophetic of what this article is talking about. Cancel-culture, call outs, etc. are creating a cold culture of obedience and conformity and of course we are seeing these things seep into social institutions like schools and younger and younger ages.
I'd agree that a lot of what he thinks about "knowledge" and "power" and are pretty wrong and dangerous. His ideas on "Bio-power" and other criticisms of science and liberalism in general are trash. The idea that everything is about "power" and "power relations" is garbage. People have taken these bad ideas too far IMO.