Everyone has the right to privacy; however, the impact of a known person's "personal matters" drastically changes the minute one chooses the public arena as a means of livelihood.
Once a person decides to enter into "Show Business," "Politics," or "Big Business" their public life, which includes almost any social setting, changes and they need to accept the responsibilities that come with fame and fortune. An argument can be made that the artistic talents of an individual are used to display the tendencies and habits of a society over a specific duration of time. This is in fact how we define "culture."
Celebrities should realize, and accept, that the paparazzi are an undoubtedly realistic opportunity cost when one chooses to enter the entertainment industry. This cost should be carefully calculated when making career choices. The public after all ends up paying the bill not only in the literal sense of receipts and taxes, bust dually in the result of positive and negative externalities. Celebrities, whether they like it or not, are ambassadors to the public and should only promote those values which they personally view to be completely genuine and human, as their actions have direct effects on the behavior of a populous.
The ambiance of the nation greatly depends upon the attitude that is created by its artists/celebrities. The person who is honored to be considered an artist/celebrity must accept the responsibility of improving the nation's ethos, and behave in a manner that is representative of the people (a quasi-inter/national/cultural/lingual representative).
I would make the claim that most celebrities are in fact artists [whether it be visual, auditory, transactional (business), or gubernatorial (statesmanship)]. An adequate artist requires a certain amount of knowledge, maturity, and insight that should be expressive of not only the individual, but also of the society as a whole.
This then is where the question lies. It is not whether or not closeted celebrities have a right to privacy (they never will, this is what they signed up for it), but rather what is the social optimum for celebrity privacy; and finally, how do we as a society limit or promote the actions of a celebrity to help shape a representative social conscience?
a combination of the readings from my undergraduate education at the University of Chicago.