Usually best to identify what the post is about. A lit of people will just pass it by.
Look at the actual study and you’ll see that there’s only weak negative correlation between intelligence and religiosity. (-0.20 to -0.23) No meaningful conclusions can be drawn from the study.
In particular, you can not logically say that people are religious BECAUSE they are not as intelligent.
Those who trumpet studies like this might be lacking in intelligence however.