Alice, you have heard that old saying " you couldn't make it up"? well 'they' just do.
We have had the physics challenged: with a man carrying a child out of a small window not managing to leave any DNA not a morsel, but still they believed it and agued that point...then they found a key from someone, then we had a wee truth slip out that the door was unlocked , but still they maintained it was a window job!
Yes, you can make it up.... lol!
Why do you keep making this claim? Having found the window open and their daughter missing - their first thought was that someone had broken into Madeleines bedroom via the window and taken her. Not to have believed that at that point would have been abnormal IMO. As time went on they realised that there may have been other reasons why the window was opened and that the abductor could have entered via the patio door or had a key to the front door. Your claim that they maintain that Madeleine was abducted via the window is simply not true.
The truth didn't 'slip out' about the patio door being unlocked. Gerry mentioned it in his first interview.
The fact that no evidence was found doesn't mean no evidence ever existed - as it may have been destroyed by the amount of traffic in 5A before the forensic bods arrived.
In any case not all of the evidence that was collected has been identified as having no bearing on the case.