Last May a TV news station in Australia staked out a bathhouse and taped transport minister David Campbell leaving. Gay blogs in America were calling it "Australia's George Rekers," even though no one could really show any reason to believe he as a homophobic politician, proving that outing often has less to do with a pol's supposed hypocrisy and more to do with the shock value of exposing the sexy secrets of the rich and famous.
After an investigation, the Australian Communications and Media Authority let the station off the hook for violating Campbell's privacy, even if their reasoning is a bit convoluted. What I've read implies that it would have been wrong for the station to have aired the video of Campbell leaving the bathhouse if Campbell didn't find out about it and resign preemptively. Since he did, the video became newsworthy in that it showed why Campbell resigned.
All I know is that Western culture has lots of problems with sex and wants to regulate sex and sexuality closely, all while people are obsessed with sex and love having sex and have sex all the time, mostly not in one man/one woman, missionary position, within marriage, for-procreation-only arrangements. Privacy is one of the few means we have to negotiate that major conflict. In fact, it's just about the only thing that's keeping our societies from being ripped apart; if everyone's sex lives suddenly became public, we'd have a lot of rethinking to do.