No @swamidass – I would suggest you need to take a closer look at this data.
It shows the three categories other than “very religious” have considerably lower (2/3 to 1/2) levels for Flat earth than for the general population, but “very religious” is over two and a half times the general population level.
That is a clear difference. And this data clearly supports my contention that it “has something to do with religion” (please note I only said “something”, not everything).
Yes, but contrast this with the low (17%) “Not religious at all” level among Flat Earthers. This means we cannot make the easy assumption that Flat Earthers are Millennial Nones.
Also, Millennials may be twice as likely (2%->4%) to be Flat Earth, but “very religious” are two and a half times (20%->52%) likely – meaning that the religious effect is still more prominent than the youth effect.
I would further note that you have not provided a citation for your unsubstantiated “most flat eartherism has nothing to do with the Bible” claim. I ask this because, although I have not found any demographic data on this point, I have come across considerable anecdotal reports of people citing the Bible in support of their Flat Earth beliefs.
Addendum:
I would tend to agree with this, but would suggest that this does not necessarilly disassociate Flat Earth from religious belief, as at least a significant minority of religious people may have similar thinking and distrust.