Yes it's plain that the McCann's have some friends who were able to help gather attention to the case - they do know one or two people in tv and the media, this was pointed out in a BBC feature not long ago. There's nothing guilty about knowing such people or wanting to use those contacts, but the point where it gets troublesome is that they've used this overlong, intense and well orchestrated media campaign to sell their own ideas of what happened, and to influence and pressurize the work of the police, the crime investigation.
Generally it's a no-no that the person/s who are bringing a case or who suffered damage would be let in on the investigations to guide them, apart from being heard by the police. They're not given the gears to heavily sway how something is treated by the police or prosecutors. The reason is plain: we don't want the police and the law to be driven to become pawns of the personal wishes of people, however angry or hurt they may feel. The law should not be a vendetta game, and if one party is "sitting in" or pressuring the inquest that's where you may land. The inquest going on now in London about the death of princess Diana shows, I think, that there's been heavy lobbying and attempts to influence the judiciary in that case in the ten years gone by, though this time around the court seems determined not to let the people around the case run the proceedings.
By selling the idea that Madeline was abducted - not killed or accidentally dead at Prada de Luz - her parents have been able to strongly discourage the police from looking too closely into the case from the point that the girl could be dead, and police investigations of this kind often do need to focus and concentrate their punch to be effective.
Now if she was abducted, why haven't those guys come out and made a demand for a ransom? The idea that she'd have been taken away by paedophhiles or traffickers is not likely.
The couple created a kind of media wall that made it very uncomfortable to make house searches, to question up close the McCanns and the other families who had lived near them. I haven't followed this in high detail, but it seems plain that almost from the start the parents and the British media presented the Portuguese cops as incompetent, and hinted if these got too close that they were throwing muck at the McCanns. TV and papers from the rest of the world just followed the UK dailies.
Now that's nothing very strange: it's a knee-jerk reaction in most countries that if one "of our own", not a known criminal and not a dope smuggler (exception!) but a countryman is connected to a crime abroad, the domestic media will side with this person and defend him/her against "corrupt cops" and "local thugs" in Greece, Thailand or wherever..But it's unusual that people who are actively "in the case" on one side are influencing that kind of media colouring (or is it more common than we'd like to think?)
After the McCanns returned to England they have started talking of setting up a parallel investigation because, again, the Portuguese cops (assisted by Scotland Yard) are not doing their job properly and are indulging in slandering the McCanns. This is ludicrous, they should understand that now they are actually suspects they shouldn't have anything to do with running the investigation and least of all set up their own search force. I know this is sometimes not how it happens in tv crime fiction, where it's kind of regular that the suspected have to find the evidence themselves to clear their names, but we're not talking McGyver here. I think it's beyond question they knew they were mounting a media offensive almost from the start.
If the parents did kill their girl in a premeditated way and then at once mounted this "Find Madeline!" campaign, they'd come out as very coldblooded, almost psychopathic. It seems more likely to me that her death was an accident and they felt a need to cover it up. Whatever, it's possible that there will never be a conclusive outcome in court. It may be impossible to prove now that the parents or anyone else were cause of her death; the dna traces in that rental car won't get anyone sentenced if it rests just on that piece (the abductors could have used the same car!) When you want to solve a murder, the best chance is to get the vital leads quickly; after just two weeks it may be cold.
I'm really less concerned whether Mrs McCann is a monster or a saint than with how the media have helped exploit the story. As ladygstar and yourself pointed out, if a single black mom in Lewisham had left her kids unguarded when she went to the pub for a few hours, the social services would have taken them from her. Yes, perhaps, but if a robber had got in before and killed or maimed the kids? Then the mom surely would have been lambasted in every newspaper from Aberdeen to Jersey.