They don't ask for your religion. They ask if you are member in one of a few religious communities. You may say that this is nitpicking but it's really not. They don't care about beliefs but just perform a service for those communities that asked them to do it. That tax is best to be thought of a membership fee that happens to be collected by the state.

If a religious community does not want to participate in that scheme they can. Plenty don't use that service.