Look at how we have commenters here running around downplaying it or suggesting that she’s making it up. A legal case is going to expose her to much greater scrutiny, and it’s both expensive and time consuming even if you win. It takes time to prepare for that even if you’re confident that you’ll win.
She had to gather evidence first. If the facts are truly as the article lays them out to be then this is a slam dunk for her legal team and a nice payday for everyone.
I'm not sure how she could have proof of any of the accusations beyond perhaps crass emails as circumstantial evidence. A lot of it is the sort of stuff that doesn't leave a paper trail, I doubt there was an official email declaring the server area the masturbation zone, maybe there was something with a double entendre though.