[germanier]

Sorry, that page is a complete misinterpretation of the actual laws. This question is only of declaratory nature of already established facts and has no influence on the actual taxation status (if it ever becomes a court case that is thoroughly examined). You do not become a member of a religious entity by answering a question there (the state has no power at all to decide to admitting new members) – mistakes made while filling the form are always curable. It's the same thing as with marriage status on the same form: You do not simply become married by answering a question there wrongly nor can you claim tax benefits by doing so.

There is no difference between the "Körperschaft des Öffentlichen Rechts Katholische Kirche Deutschland" and the worldwide catholic church. That's a single entity.

(I say that as a non-religious person that never has been a member of a religious entity. If a community decides to tax its members they should be free to.)