I changed the title slightly because the original article title was kind of clunky and potentially unclear.

Some more context from the NYU student newspaper:

https://nyunews.com/news/2021/03/24/gsoc-uaw-union-strike-vo...

https://nyunews.com/news/2021/04/23/nyu-gsoc-graduate-studen...

https://nyunews.com/news/2021/04/29/gsoc-strike-update-media...

The idea of going on strike for something you are paying for is just mind boggling to me

Lots of graduate students are employed by the university they attend. When I was a graduate student I was employed to teach classes. I also was a client of the university since I paid some tuition/fees to attend classes there. I presume they’d be going on strike as employees and the graduate students that are not employed would not be going on strike.

This is correct. They are unionized and striking as employees and not as students.