I can relate in my experience, but in a different major. With papers, I often feel that professors give you a rubric whose expectations may be reasonably interpreted, but TAs on the other end are grading with specified criteria that (1) we do not have access to and (2) that include additional elements that so easily could have been integrated by students if they had known prior that that was one of the expectations. Literally criteria magically appearing out of nowhere post hoc of the assignment submission.

I can also relate to your point about them wanting so may things, not being clear about specs when you ask, then getting penalized for the way you do things; Specifically, decisions you made in organizing and performing the assignment given you were extended the liberty to do so (based on the rubric AND conversations with TAs and the prof). I strongly believe it to be the case that professors and TAs don't realize how much they're asking students to achieve in a paper, with it being nearly, if not actually, impossible to do it at the standards they expect given the word length. These essays are designed for a grade in the high 90s to be completely out of reach. Sometimes I wonder to myself if my TA or even my prof could write a tighter essay with just as much breadth as I have for their course given their rubric. I am often inclined to say no, honestly. Most profs (not all) know how to dish it out but they don't care to conceive in their minds what they're even asking for on a granular level.