Antitheists have it backwards

I would suggest that this is a profound misunderstanding among the antitheists about if and how religion and stupidity are causally connected.

A stupid person may become religious, or they may not, but they will still be stupid. An intelligent person may or may not become religious, and they will still be intelligent. True, some beliefs are ideas that posses the mind, not ideas the mind possesses, but this is not true in and of the ideas themselves. They are a function at least as much of the person holding them. So yes, under some circumstances, some ideas can actually make you stupider, and some ideas (cough cough FLAT EARTH) it’s just not possible to hold without being an idiot. Believing in the literal truth of parts of many religious truths is insane. But assuming that all religious people believe in the literal truth of their texts is equally bonkers.

In short, the causal relation probably goes largely in the direction opposite to what’s assumed. People who are religious nutters would probably have just become some other type of nutter if there wasn’t a religion to follow.

Or perhaps, to refine this a little... it's not exactly that stupid people become religious or that religion makes you stupid. A stupid religious person will believe stupid religious things. An intelligent religious person will believe intelligent religious things. The stupid one may follow their beliefs rigidly and because they've been told they're correct, but equally, the intelligent one may believe what they do because they genuinely seem to them to be correct - they will understand not to apply them inflexibly or unquestionably.

There is also as a nice atheist take on Pascal’s Wager which boils down to : you can’t choose what to believe. Hence pretending to believe in God makes no sense. This is entirely fair. But surely by the same token, by what grounds should it therefore be acceptable to discriminate against the religious ? They no more choose to believe than they choose their skin colour. You could instead try treating people as individuals, examining what they actually do instead of what they say, and stop assuming they must adhere to a very childish view of what religion is supposed to be… my grandmother was a racist old bat who self-identified as a Christian but didn’t believe in an afterlife; my most valuable mentor in astronomy is a Catholic. People are, in short, complicated, and treating them as simple tends not to accomplish very much.

Or to finish with an unpopular opinion... it's not that there are so many religious idiots in America because religion has been allowed to freely dominate there, as opposed to secular Europe... it's because American culture in general promotes idiocy. Tendency towards religious nuttery is a consequence of a root cause, not the cause itself.