If you think about what the Satanic Temple has accomplished recently, it’s impressive for any group, much less one you didn’t even know existed before 2013.
They pressured Oklahoma to reconsider a Ten Commandments monument at its State Capitol building because they wanted a statue of Baphomet in the same space. (The Christian monument was eventually deemed illegal, anyway.) They got a Florida school district to ban Bible distributions because they wanted to give away Satanic-themed coloring books. They got a Satanic display in the Florida State Capitol building to join the Nativity scene last winter. And, perhaps most significantly, they sued the Governor of Missouri on behalf of a member who didn’t want to wait for the 72-hour mandatory waiting period to pass before she could obtain an abortion. She used the argument that waiting so long violated her “religious freedom.”
It’s easy to forget that the Satanic Temple doesn’t actually believe in anything supernatural, including Satan. Yet they’ve forced government officials to recognize that if they want to grant privileges to the Christian majority by saying the door is open to all religions, they may have to treat Satanists the same way. It’s an argument that doesn’t always work with atheist groups who explicitly reject God.