Unfortunately many people don't react on reason without an emotional component. "X really happened" can help there. That fits the Facebook situation rather wel

Unfortunately many people don't react on reason without an emotional component. "X really happened" can help there. That fits the Facebook situation rather well: "Oh, they want you to give a real name snicker Seymour Butz will do". There used to be an expectation that such rules aren't really enforced. Now they are, and it's notable that Facebook picks a method (reporting on your friends) with a certain tradition. As a side note: That approach and "don't complain" go well together: said tradition didn't favor free speech, either.