And furthermore, Rapp had indeed told many people about the incident over the intervening years. News sources were able confirm that he told others as long ago as 1990. He also had been told by a lawyer that it was not worth pursuing charges. In 2001, The Advocate even redacted Spacey's name in a piece they ran with Rapp in which he described the incident.
Rapp didn't change his stance or his story- it was the world that changed.
And yes, Spacey has many accusers. Rapp is merely the most well-known. And I suspect there are many that haven't or won't come forward.
"...everyone finally shut up, and the audience could enjoy the beginning of the Anatevka Pogram in peace."