That is why generally they look to supporting evidence and collect witness statements to collaborate accounts as they did with the McCanns.
And those accounts did not corroborate though did they? Look at the number of discrepancies and the changes of stories, the shoe horning in of Bundleman and the Payne visit. Look at the Rog interviews and the men's changed timings for when they left the tennis match. It was a whole series of huge contradictions and apparent collusion which necessitated further more detailed investigation.
I understand your point that people do lie to evade being suspected however they did cooperate with the initial investigation, they were in contact with the police however once it became clear to them that they were still suspected even though they had cast iron alibis it’s not hard to understand why they would turn down the invitation for a reconstruction.
What cast iron albi's? There are none that removes the possibility of involvement. What co-operation? They gave witness statements which didn't tally with the evidence indications or each other.
To be fair to them and the PJ there could have been a whole host of mitigating circumstances as to why a reconstruction was pointless, I can only point out the obvious one which is that it served no purpose in bringing Madeleine home. The only advantage I can possibly see is if they had done one it would have silenced the conspiracy theorists until they found something else to latch on to and throw back in their faces. The nature of any accomplished and polished conspiracy theorist is the ability to go in at a granular level and study something in total isolation and to the of contrary supporting evidence in which to hatch a new myth.
No it wasn't pointless it was trying to see if what the parents claim happened could physically happen. If it could not then they needed to explain why their statements didn't tally with the reality.
It's nothing to do with conspiracy theories, it's to do with making sense of the accounts of the last people and witnesses to see the missing child and to see how those accounts tallied with the evidence collected and if they didn't tally for those witnesses, like any witness in any investigation in the world, to explain why their accounts did not match up to what was shown in the reconstruction.
The best they could achieve from the reconstruction was determining what possible route the person who took Madeleine went based on view points and line of sight. Other than that, it’s a futile exercise I reckon.
No you have also made the mistake of presuming the reconstruction was to be taken from the point after the parents had been ruled out. \They hadn't, they had to rule themselves out by showing the PJ that their sworn statements were viable and corr3ect in real world conditions.