[qs]I think that is a pretty simple explanation[qs]
And an incredibly stupid one.
First the site you linked to stated that
only 40% of scientists with a B.S. believe in a personal God, thus 60% deny the existence of a personal God. That's hardly a significant margin especially when taken from only one source.
But I wouldn't be surprised that more scientists deny the existence of a personal God than affirm it. But so what. That's one moment in time when you can say that. The same poll over the previous centuries of scientists would no doubt reveal a starkly different result. So what does that mean? Just that the correlation between science or "intelligence" and faith in a personal God is fluid over time, not static.
BTW, your study explicitly refers to a personal God AND an afterlife. Which means that all those Deists - all those who believe in a God, just not a personal one, or all those who deny the afterlife, are included in the non-believing category.