Actually, if religious wackos disappeared, IQs would plummet because IQ scores are based off a bell curve and a large portion of the low end of the bell curve would disappear, shifting the average which would lower most people’s IQ.

Violence would also go down. The Venn diagram of religious whackos and anti-maskers is nearly a circle, and during COVID lockdowns at least here in Finland there was a lot less disorderly conduct in eg. bars when they required proof of vaccination – all the conservative nutballs stayed at home and didn’t start beating people up (well, not in bars anyhow. Spousal abuse went way up…)