Earlier quoted context omitted.
Sure, it seems to agree with those studies. But let's suppose that the religion vs word length chart is a valid measure of intelligence. Are you then prepared to defend the same conclusion about the race vs word length chart? Or will you start looking for confounding factors, eg, Latinos trend Catholic? If so, think about why you accepted the religion claim on its face, but examined the race claim more carefully.
Because religion is a choice based on personal beliefs and/or reason (but usually the former). Race is a state of being. I'm not quite sure what you're trying to get at.
Religion is mostly based on what you grow up with, i.e. what your parents told you. Turns out, race is also highly correlated to your parents.