Re: The complaint seems confused
"This may well be true but does it predict better than random? This might have value to advertisers."
Let's assume, for the sake of argument, that gender-targeting ads works (I'm not so sure about that). Then if you misidentify a significant proportion of users and serve them the wrong content your advertising is likely to be less effective than when you serve neutral or random ads - a lot of folk might be a bit sensitive about having their gender misidentified :).
Though it can be good for a laugh - in so far as adverts register with me I've noticed that I've been served a lot of ads aimed at plus-sized German-speaking ladies who favour drab-coloured clothing. If that targeting is based on my search history a lot of them must also be interested in loadcells, chainsaws and stain-isolating paint. Inspiration for a novel, anyone?