I think what you say is true in some cases where the evidence can be interpreted in different ways. I think in this case the evidence sceptics use does not stand up to scrutiny and is flawed. All the evidence used to make the McCanns arguidos was later not confirmed. Ie there was no evidence to support the accusations which appears still to be the case. Pedro do Carmo of the PJ said the McCanns are not suspects and there's no evidence against them.
Your analogy of creationism shows that some will passionately believe something which is patently untrue and believe there is evidence to support it when there's not.
It's a very good analogy
I don't see this case being any different to the other cases I've looked at. Have you looked at any other cases in any sort of detail?
There are many who view the T9 as having some involvement and its by no means limited to the likes of those here on social media. Eg Pat Browne, criminal profiler and Craig Murry, former British diplomat to name just two.
The fact you perceive something a certain way which causes you to form certain beliefs doesn't make you right when you're unable to prove them.
I believe MM was abducted by person(s) unknown to her and I don't believe in any deity, neither of which I can prove so this doesn't make me right. It just means I have formed opinions and beliefs which many others will disagree with and they are perfectly entitled to do so.
And imo the McCanns have been absolute fools in attempting to silence their critics through libel law. Of course Carter-Ruck were happy to oblige it is after all what they do for a living but in whose best interest?