Lol. Your question assumes the diary was real, was not tampered with or reproduced. It has never been confirmed that it was her diary. What she wrote in it has not been confirmed nor is there any context whatsoever if it is hers.
Do you know anything about about how it was obtained or Veritas and their involvement? Do you know they refused to confirm it’s authenticity?
As I asked before, if true, do you know anything about the circumstances of the alleged act? Of course you don’t. You assume Biden showered with his, what, teenage daughter?
This is explains it well, step by step. And yes, the article does say it seems likely it’s her diary.
Plenty of evidence and reporting suggests it is likely real, but that doesn't mean the government has publicly stated an opinion on it.
www.snopes.com