When you say Facebook is "selling data", I think most people would understand it to mean that advertisers can go to Facebook and buy a list of people who eat at McDonalds. That's very different from the opaque ad targeting Facebook actually sells.
In the end you have a click associated with an advertising campaign linked to a real life (or even pseudo) identity.
It doesn't really matter if ads are served to everyone or if they are shown only to a targeted demographic - either way, only people who are interested will click on them. Also, I think it is safe to say that, roughly, it is only the efficiency of clicks per ad-view that will increase if one uses targeted advertising.
So, if the act of clicking a targeted advertisement does not in itself somehow "transfer" any more identifying data than a click on a regular ad would, which I don't think it does, then what's the problem?