I've never been a grad teaching assistant so I can't speak from personal experience. I know they work for some professor(s) doing various things and in return they get some financial aid. I'm sure some professors are jerks. I'll bet the money is thin. In some cases they might deserve more. But somehow the whole thing reminds me of this story https://www.inc.com/alison-green/about-those-interns-fired-for-petitioning-for-a-more-casual-dress-code-.html
Have a thread on this in the political section. Never worked as a TA, but I'm really struggling to agree with their position.