I was told that there was absolutely no motive for the McCanns to simulate an abduction. I offered a motive based on evidence. End of.
Load of rubbish. You said it yourself - "there's no evidence the McCanns sedated their children". You can't say that theory/motive is "based on evidence" based on the fact that Kate suggested an abductor might have sedated Madeleine.
Amaral suggested the parents staged an abduction. So if someone were to come along now and now propose a theory that it was actually Amaral who staged the abduction himself, and they made the claim that this theory was "based on evidence"... you would make no objection to that argument, would you?
As I said, it takes a lot of imagination and barrel scraping to come up with a motive for the McCanns to have covered up her death. There is no evidence that supports a plausible motive IMO. On the other hand, there's plenty of evidence to support a plausible motive in the case of CB. End of.