Probably because of the power dynamic makes it really hard to see how free that "choice" really is.
And also puts doubt on any decisions by the boss that affect the employee - companies don't want people "sleeping their way to the top" as that's not putting the business' needs first.
"All men command women, we command all men, and our women command us." - Cato
This is a very successful woman, career wise. She’s clearly not incapable of navigating high stakes power dynamics and you shouldn’t just absolve her of responsibility in this.
(Your second statement carries far more weight)