I don't know that it's intelligence per se. For some, it's ignorance and/or anti-intellectualism. For others, it's more a need to have some authority to dictate right or wrong, good or bad, etc. For others it's a license to vent bigotry without guilt. Slave owners used the Bible to justify owning blacks just as "conservative Christians" today use it to justify their homophobia while wearing clothing of blended fabric and eating ham sandwiches.