While I support women doing whatever they want to with their bodies, for money or for free, it's not exactly a suprise that a Catholic school would not consider that to be "appropriate" behavior. To a large extent, private institutions do have the right to create their own rules.

Whether or not sex work is empowering or exploitive largely depends on the individual circumstances, since it can certainly be either. I do agree that stigmatizing the woman, and not the man who was on OnlyFans as a customer who "discovered" her there is a tired old patriarchal trope. I hope her business increased from the publicity.