It depends on the severity of the "mistake". DUI? Date rape? Child abuse? Murder? Plagiarism? Shoplifting? Swearing? Where do you draw the line? Rape is pretty damn serious.
I agree that the severity of the mistake is important. It's not clear to me that this was rape. It could be though. Date/relation rape is sometimes a hazy thing. I'm not excusing it, but I think it's difficult. And the fact that his accuser is not named is a problem. And why bring it out now?