Satanism isn't an organized religion. Some are atheists, some are agnostic, some are deists or pantheists, some are monotheists and others are polytheists. It depends on the person or group. Most of them don't accept the Christian paradigm and are closer to Pagans.
Then it's just as organized as Christianity.
Some Christians believe in a literal interpretation of the Bible, and some don't.
Some believe in a literal hell, and some don't.
Some believe in salvation by grace, and some believe in salvation by works.
Some believe Saturday is the holy week day, and some believe Sunday is.
Some believe in baptism by immersion, and some believe in baptism by sprinkling.
Some take the Bible as the "true authority," and some take only the New testament, and some take their church's creeds, councils, cannons, tradition, laws, and their pope.
Some believe the bread and wine taken at communion are olny symbolic, and some believe they are the actual body and blood of Christ.
Some believe the Bible is the only holy book, and some believe there are other holy writings.
Some marry GLBTQ's, and some don't.
Some ordain women, and some don't.
Some baptize infants, and some don't.
Some subscribe to the doctrine of the Immaculate Conception, and some don't.
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