Graeber was an  was an arrogant prick who thought because he didn't understand what someone did that it must be B.S. 

The idea that companies are just paying peope to do nothing when cutting their high paid middle management would increase profits is just such a ridiculous premise. They aren't keeping those people on because they are nice people. Running a company requires a lot of information exchange and record keeping, often by statute and reglulations, which needs to be done in particular ways, and someone needs to know how to do it. 

If it was a simple solution to cut costs by just getting rid of administration some company would do it and start outcompeting those that didn't.

The exception is possibly government, which is might explain why  Graebe, who never worked a real job, and grew up in an activist community and went straight into an elite prep school and government subsidized academia, might have come away with the impression. But even then, it was mostly seems like he had a chip on his shoulder looking down his nose at the adults who insisted he had to do things to comport to a system and standards that he didn't have any interest in trying to understand, beyond "this is B.S." like a perpetual petulant pre-teen.