If this woman's claims were false they would do best to keep quiet and wait for the legal process. They have a huge advantage with both the money to pay lawyers and many fawning media outlets willing to support them so if they were in the right they would be guaranteed to win if they just waited it out.
Going on the offensive is dangerous because it makes them look bad and draws more attention to the story.
Attacking this woman would be very stupid unless they are actually in the wrong, in which case it makes perfect sense as an attempt to intimidate other employees into not speaking out.