Gimp has the point I think is pertinent. For all the observers who have said (mostly elsewhere) that "a rule is a rule", the actual rule says that unsportsmanlike conduct may include (the actions listed). The way it's written leaves a lot of discretion to the referee....but it's all depending on what is unsportsmanlike. The Princeton wrestler's dropping his headgear was not unsportsmanlike.
There is plenty of stuff that happens on and around the mat that doesn't get called. Vito slammed his fist on the mat and used a bad word when he gave up a takedown to Glory in the 3rd period of their NCAA semi's match in '22. I certainly wouldn't have called that, and the ref didn't. It probably never occurred to him.
I wonder if the ref thought he had no choice. It looked to me as though that's what they were communicating when JoeD questioned the call.