This is misguided because it assumes a) that the problem is related to the person being discriminated against, b) that only women are discriminated against.
The preference for women means less opportunity for gay men, disabled men coloured men, etc. either because it is a perfectly good excuse to say that their company is diverse (when it really isn't) and because there are less jobs available.
Diversity means just that, i.e. a lack of differences in peoples experiences and characteristics. Even when they have 50% male 50% female on the board, they will still be mostly straight , able bodied, white, and middle to upper class, and in Britain most likely went to the same schools. And also you will still see that the grounds and windows cleaner are men and that the secretaries, receptionist, and office cleaners are women.