"Religious bigot" is a term used to stigmatize people that pose irrefutably good arguments as to why organized religions are antisocial institutions and harmful to humanity. Otherwise known as an "Ad Hominem," people from religious orientations often attack the people making arguments against their beliefs as opposed to their actual arguments.
1. "John says that my religion is destructive to humanity."
2. "John is a religious bigot, and likes to masturbate to furry porn."
3. "Therefore, John's argument is false. How could you trust a bigot that faps to furries?"