To me, that whole line of argument makes no sense. Facebook is at its core and from the start an anti-privacy entity. It relies on encouraging people to post their whole lives and the lives of others. A privacy-friendly Facebook would not be Facebook at all except in name.

Taking your legislation example, a privacy-minded person investing in Facebook would not just like be a legislator disagreeing with a decision, it'd be like a self-proclaimed anarchist pushing for a more powerful government.