I have no idea what the true religious beliefs of the Satanic Temple are. But of course, that's irrelevant. This is obviously just poking fun - pointing out the hypocrisy of our laws regarding religion.
The tax exemption thing, in particular, is a complete inversion of the intent of the First Amendment. It's pretty clear. It says "Congress shall make no law respecting an establishment of religion...". But the tax exemption does exactly that. By granting special perks to some religions - only those duly recognized by the state are awarded this prize - Congress is doing exactly what the founders wanted to avoid.
The tax exemption thing, in particular, is a complete inversion of the intent of the First Amendment. It's pretty clear. It says "Congress shall make no law respecting an establishment of religion...". But the tax exemption does exactly that. By granting special perks to some religions - only those duly recognized by the state are awarded this prize - Congress is doing exactly what the founders wanted to avoid.