beau99 wrote:There are a few (and I literally mean "few") Japanese bands who are anti-everything (including both of those religions), however none of their names are appropriate for this site so I can't say who. But I imagine they're just doing that for shock value and don't actually do it in real life (much like Slipknot and Marilyn Manson here).
Marilyn Manson has been known to respond to his critics that his performance persona has done nothing but satire the beliefs and actions of mainstream society, and thus they are in fact not so much criticizing him as criticizing themselves (which he has expressed in songs like Disposable Teens). From my own reading, religion has been in major decline in Japan for a plethora of reasons, and so, while I can't point out any such songs or bands, there's all the reason in the world to think they would exist (especially among music for alternative youth subcultures).