That's confirmation bias -- your remark does not prove that those women aren't concerned about misuse of their photos. Maybe they are concerned but use Facebook despite those fears because they can't afford to be ostracized by your social circle for not being on Facebook.

I've definitely had female friends leave Facebook because of the "creeper" problem; others use a fake profile picture (e.g. a cartoon or a drawing) because Facebook profile pictures are world-readable by design; others even use fake names so that you can't search for them (say, "Stone Steps") unless you talk to them IRL and ask them to add you first. It's sub-10% of my friend group, but it's the sort of trend that leads to services like SnapChat taking off.

That's not confirmation bias, unfortunately. The argument was not that women aren't concerned, although I would also argue that they, in general, are not.

Bias aware bias: the tendency to bring up biases in an online argument, regardless of their definition or relevancy.

As far as I can tell, the argument was, "All 50 women I know are on Facebook, therefore less than 1 in 10,000 women have noticed their Facebook photos are harvested for use on shady dating websites." That doesn't logically follow.

I'd argue your remark is an ad hominem attack because latched onto my use of the word "bias" rather than refuting my argument with data.

On facebook, but do they really use it in a manner profitable to advertisers? Those I know have erected behavioral barriers to protect themselves (privacy settings, not clicking things, quick unfriending) that limit their marketability to advertisers.