Of course celebrities deserve some level of privacy. Their right to this is ingrained in British Law (Through the European Human Rights Act) and reinforced by the press code of conduct in it's "Right to Privacy" section. Just because aspects of your job may put you in the public eye does not mean you have given licence for your whole life to be scrutinised in the spotlight. However, we must not allow this right to be exploited by celebrities who want to profit from and pick and chose how they are portrayed in the media - for example those who will sell their wedding to Hello for 300,000 but become indignant when anyone wants to write or read about their subsequent divorce.
To allow this to happen would create a situation where the media becomes completely censored and powerless to scrutinise any PR constructed persona. PR fakery would rule the world - no-one would be capable of challenging it.
I have the utmost respect for the privacy of the actor who performs on TV or in films then quietly gets on with their own life outside this work. The same for the presenter, chef, singer and sports person who do the same. But the "reality star" who seeks out publicity and creates a "job" for themselves which hinges on them being in the papers as much as possible, getting paid to turn up to parties and talking about aspects of their private life on camera does not have the same right to suddenly demand the spotlight be turned off just because they fear they may be looked on unfavourably.
It is also important to remember that there are situations when the public has a right to know they are being mislead. For example - a celebrity chef whose entire career is hinged on him being a "family man". His family get paid to appear on telly with him, he uses them to "brand" his product. If this man is having an affair, I believe the public have the right to know the brand they are buying into is a lie.
Perhaps the real question that should be asked here is where does the public's insatiable appetite to read about people's private lives come from, and is this something that can be switched off? Because, one thing is for sure, while people still want to read and see this stuff there will always be someone working hard to make money from photographing and writing it.