Another correlational study, but I'd guess that societies that have the time, energy, and resources to spend in the creation and cultivation of multiple religions are also those that are advanced enough to understand and practice good hygiene and medicine.
Societies where people are dropping like flies from disease and filth don't have the same time and energy to engage in philosophical debates about which god is the correct god (or even if "god(s)" exist at all... aka atheism). Those societies probably have a single religion, put in place to explain the misery of life, enforced by the community upon everyone, and are likely intolerant of dissenting opinions. Dissenters have too much other shit to worry about (literally) than challenging the local witch-doctor.
Still... it's just a correlation so who really knows what's going on.
Societies where people are dropping like flies from disease and filth don't have the same time and energy to engage in philosophical debates about which god is the correct god (or even if "god(s)" exist at all... aka atheism). Those societies probably have a single religion, put in place to explain the misery of life, enforced by the community upon everyone, and are likely intolerant of dissenting opinions. Dissenters have too much other shit to worry about (literally) than challenging the local witch-doctor.
Still... it's just a correlation so who really knows what's going on.
How about they have a rigid belief system and they are intolerant of those who do not share it, just like people in religious/xenophobic societies?