So everyone is presumed guilty then? When people choose not to take part in a reconstruction they are exercising their presumption of innocence in practice. They most certainly are not choosing to remain suspects. Your view is a presumption of guilt that puts the onus on them to prove innocence. That is the wrong way round. Like them or not the McCanns are entitled to be presumed innocent. They do not have to prove anything. That is what innocent until proven guilty means and the presumption of innocence remains until such time as guilt has been proven. That is for everyone, not just the McCanns.
No, you like other McCann supporters, are confusing the difference between police investigation and criminal trial.
Under law and in a court they are innocenct until proven guilty.
In an investigation all those who may be suspected to have had the opportunity to be involved in a crime have to rule themselves out of the police investigation to satisfy the police they are not involved. This can take the form of verifiable alibi or physical distance away from the crime scene for example.
When a suspect does not provide evidence of innocence they are not then guilty, far from it, that's where evidence then comes in, but they remain a suspect until such time as they can be ruled out with definitive and verifiable evidence (including of course guilt against another suspect) or until evidence is discovered which shows guilt of those suspects.
As the McCann's have not been able to rule themselves out (and the AG report specifically states the effort they and their friends expended to cancel the reconstruction is directly attributable) in the Portuguese investigation (currently shelved) they will remain suspects (although not arguidos).