In other words everyone should subjugate themselves to the needs of a pair of parents who mislaid their child, and disregard the insulting implication that they are child-snatchers? Never mind if you're accused, just roll over and accept it? Really?
Well you have the police interviewing people if there has been a murder say, people who were in the vicinity of the crime.
They are not saying they are the murderer, but they need to interview them to make sure they had nothing to do with the murder.
If you get parents who have a child who looks like Madeleine, is the right age has the mark in her eye, then I would think the parents would think, perhaps one day something will report a sighting of our child and we will have to prove she isn't Madeleine McCann. The same as if someone looked exactly like someone who murdered someone would have to prove it wasn't him/her.
I doubt if the parents are going to be nasty about it, just resigned to the fact. After all when proof is given then they are cleared aren't they?