If you want to discuss morals, then neither side is morally fruitful.
One side left their children at home, then went on a media circus when one of them went missing and no matter how you put it, they made money based upon their bad decisions and because no-one believed Goncalo Amaral (I do, I think he's hit the nail on the head with the hammer), well no-one who mattered, he wrote a book too.
If the Mccanns didn't want to 'benefit' from the money, they should have left the job to the police and missing persons charity. We live in a digital age, they could have sorted their own searches out from the back of a computer. Just remind me, who was looking for Madeleine when KM was writing her book (to profit from her loss) and while GM was working?
There are plenty of cases where people have had to sort their own searches out, Amy Bradley, Johnny Gosch, Natalee Holloway, in fact I can't from the top of my head think of anyone else who has taken this route to find a missing person, especially when it was their own bad judgement that caused it and how people can symphathise with the parents is beyond me. I'd put my house on the next post being "Its not about the parents, we want to find the child".