First, two issues that are regularly raised and their rebuttals:
1) Only the rich have access to superinjunctions, this creates a two-tiered system of law and is dangerous.
This is essentially true, though it is also true of any number of other areas, most of which are far more dangerous, such as the law of defamation, put to sinister use not so long ago against Simon Singh after criticism made by him of the claims of the British Chiropractic Association, or the enormous costs, stress and uncertainties which prove unsurmountable in any number of civil cases, including those falling under employment law.
There is however a key difference here, which is that generally the poor don't actually need to make use of superinjunctions in this way: Newspapers rarely expect to make money out of publishing the lurid details of a minimum wage philanderer. This falls into the 'public interest' vs 'of interest to the public' dichotomy, of course. It's all very well to say that those who live by the sword die by the sword, but that serves as no justification for papers making money by increasing the misery already caused by private wrongdoing.
2) These injunctions are taken out by powerful men, and suppress the right of the women they may have slept with to their free speech.
This is an important point, and it has importance which extends far beyond the realm of privacy law. A woman's right to free speech is extremely important, and should not be contravened where it can be avoided, but a right to free speech is not the same, nor equivalent to the right to a platform. Selling your story to a newspaper is availing yourself of a platform that most people do not enjoy.
This is why it is not and has never been reasonable to talk of 'free speech' for the media. The media certainly must be allowed to perform it's essential public duties of investigative journalism, reporting and analysis, but a newspaper or a television channel has a power to broadcast its 'free speech' to millions of people, something that you or I simply cannot hope to do. And with that platform comes responsibility-- we have a right, given their extraordinary power, to expect them to, if not tell us the truth, then avoid deliberately deceiving us. We have a right to expect due diligence, that they will try to faithfully research their stories. We have a right to expect that they will not attempt to exert their influence for commercial gain.
The point which arises out of both of these veins of argument is this: The right to free speech is not absolute nor unconditional. It must be weighted against other competing priorities, such as national security, to take the most obvious example. And it can be waived, if an individual changes the character of their speech in such a way that it moves from one category to another, such as from individual free speech to corporate projection. In the same way, privacy can also be waived. If something is done in a conspicuously public manner or place, where no reasonable expectation of privacy could be sustained, then that person has waived their right to privacy. The question is not about wealth, it is about whether the right to privacy should trump in certain cases the right to free speech, and injunctions are temporary relief in any case, they provide no permanent safety from discovery.
Of course as has been said before, much of this becomes increasingly difficult as online digital media becomes more and more powerful, but not irrelevant. We will have to face the same questions in respect of twitter or blogs, which are just as capable of fostering groupthink and prevarication as tabloid journalism ever was. In an age which empowers the ordinary person to speak and be heard, there is no easy mechanism to ensure we also listen, and show restraint. All rights spring from duties; it is when society observes its duty to protect and respect your rights, that you can be truly said to enjoy them, otherwise they are meaningless, just words.
Certain elements in the media have long despised the Human Rights Act and its slow, creeping introduction of a law of privacy into the United Kingdom. They would argue that the freedom of the press is paramount, that their right of free speech trumps the right to privacy, they talk a fine game, but in the end they have no interest in the rights of others, only their own, and while every side in an argument deserves its advocates-- the principle of audi alteram partem being fundamental to English law-- so long as those who can speak directly to millions, are able to advocate their own commercial interests, we cannot regard the sexual antics of the few to be the larger problem.