While you can argue patents are only paper, a valuable patent is worth defending. In this case, she was able to demonstrate prior art, meaning that a patent could not be granted since they have no idea to protect since it's been in the public domain (i.e. released to the world) and not an original/non-trivial idea. This is why academic publication, or in the past the use of laboratory journals, are useful in documenting time of the invention.
I'm from a scientific background. Plaigarism is the most serious allegation you can level against someone. This is a whole 'nother level.
Sure, there are plenty of people who would refrain from stealing anyway just because it’s morally wrong. But there are enough people who don’t care that the whole idea of property rights becomes meaningless in practice without some way of enforcing them.
Aside from morals, the threat of reciprocation, not by the state specifically but by the property owner who was harmed and anyone authorized to act on their behalf.
Unlike actual property, IP isn't based on reciprocation. The penalties for infringement go way beyond simply losing similar forms of IP.