Sounds like a group of lawyers said "hey, do this, just to cover your asses". This isn't really news, either. They're just doubling down on enforcing rules they've already had in place since the beginning.
Also, that was a pretty poor example of an adult star using Instagram in their favor. 163k? That's not a lot. Gianna Nicole, for instance, has 2.3 million.
https://instagram.com/officialgianna/ - 330k for Madison Ivy -
https://instagram.com/420madisonivy/?hl=en