I think right there, the part where you say 'her accusation served absolutely no purpose other than to try and derail his job promotion' - that's the part where you disbelieved her from the start because you didn't want the accusation to be true, and it would have required rock solid proof to persuade you otherwise. Yet as mook pointed out, if Ford were a family member or a personal friend of yours, probably you'd start from the opposite assumption.

It's not true, anyway, that such an inherently unprovable accusation long after the fact serves no purpose other than to try and ruin the accused's life or career, be it in Kavanaugh's case or any other. It's an important step in dealing with what has happened - being able to finally publicly speak out about it and confront the person who has assaulted you, or who you believe has assaulted you. Whether that results in any direct consequences on that person's life or not isn't really the point there.

As for should he sue - did you see the edit to my previous post? You're very keen to keep presuming the innocence of people accused of sexual assault, possibly because you have the Kavanaugh case in mind rather than other people who also can't be proven guilty but look a lot less clean. But when we're talking suing for libel or slander, it means you'd need to prove that your accuser deliberately lied in order to harm you - so now this woman becomes the accused who is innocent unless you can prove her to be guilty (yeah, it's a civil case rather than a criminal one, but still). And here you seem very keen to presume that she is indeed guilty of that - even though the general consensus among Republican senators who heard her was that she seemed compelling and seemed to be genuinely convinced of what she said.