They're not comparable. You give information willingly to Facebook and accept their terms of service. I know plenty of very social and successful people who don't use Facebook. Maybe you feel that there should still be additional regulations on Facebook; fine, that's a debate for another day. But it's very clearly different than a "journalist" prying into your private life against your will to produce a sensationalist and embarrassing article that does nothing to serve the public interest.
Frankly, I think that's just naivety: https://en.wikipedia.org/wiki/Facebook_Beacon
Sure -- I agree that they're not comparable (that said, I don't necessarily agree that FB is better than Gawker privacy wise just because it's a different model. In fact I believe the opposite -- and don't particularly care for the "volunteer" part. People volunteer to all kinds of societal harmful stuff).
But my argument above checks to see the validity of the parent's comment after "assuming that they're comparable".
Again, assuming FB and Gawker have the same privacy issues, what you point doesn't really matter.
FB's decisions might be influenced by more than just Thiel, but if Thiel feels strongly about privacy (and his views aren't heard on FB) he always has the option of selling his stock and leaving FB...