>I think the post you reply to is saying that the fact that someone believes fervently in creation over evolution actually makes them an idiot, regardless of IQ.

That stretches the definition of an idiot considerably.

>This would be because it is a firm rejection of scientific evidence in favour of belief.

That could be beneficial for one's emotional health (belief in higher power and all that) and thus the smart thing to do in some cases.

Who said "identifying reality correctly" is the smarter thing to do? Sometimes, not being too logical can have great benefits.

Here's an old argument for this:

>Origin of the Logical. — Where has logic originated in men's heads? Undoubtedly out of the illogical, the domain of which must originally lave been immense. But numberless beings who reasoned otherwise than we do at present, perished; albeit that they may have come nearer to truth than we!
Whoever, for example, could not discern the "like" often enough with regard to food, and with regard to animals dangerous to him, whoever, therefore, deduced too slowly, or was too circumspect in his deductions, had smaller probability of survival than he who in all similar cases immediately divined the equality.
The preponderating inclination, however, to deal with the similar as the equal — an illogical inclination, for there is nothing [100%] equal to another — created the whole basis of logic. It was just so (in order that the conception of [a shared] substance should originate, this being indispensable to logic, although in the strictest sense nothing actual corresponds to it) that for a long period the changing process in things had to be overlooked, and remain unperceived.
The beings not seeing correctly [and saw similar things as "same" and static] had an advantage over those who saw everything "in flux".
In itself every high degree of circumspection in conclusions, every sceptical inclination, is a great danger to life. No living being might have been preserved unless the contrary inclination — to affirm rather than suspend judgment, to mistake and fabricate rather than wait, to assent rather than deny, to decide rather than be in the right — had been cultivated with extraordinary assiduity.
The course of logical thought and reasoning in our modern brain corresponds to a process and struggle of impulses, which singly and in themselves are all very illogical and unjust ; we experience usually only the result of the struggle, so rapidly and secretly does this primitive mechanism now operate in us.

(Friedrich Nietzsche, Gaya Scienza -- with small edits in [] to make the excerpt clearer)

And here's a newer one:

>Hoffman: Right. The classic argument is that those of our ancestors who saw more accurately had a competitive advantage over those who saw less accurately and thus were more likely to pass on their genes that coded for those more accurate perceptions, so after thousands of generations we can be quite confident that we’re the offspring of those who saw accurately, and so we see accurately. That sounds very plausible. But I think it is utterly false. It misunderstands the fundamental fact about evolution, which is that it’s about fitness functions—mathematical functions that describe how well a given strategy achieves the goals of survival and reproduction. The mathematical physicist Chetan Prakash proved a theorem that I devised that says: According to evolution by natural selection, an organism that sees reality as it is will never be more fit than an organism of equal complexity that sees none of reality but is just tuned to fitness. Never.

http://www.theatlantic.com/science/archive/2016/04/the-illus...