There is no need to debate with one who's cup is already full. Actually, it is not a debate at all but a shouting match. In a debate nobody wins or loses, if there is a winner or a loser then you are not debating but arguing. Please do not try to taint the sacredness that is debate. A debate, as dictated by the ancients Greeks, is a quest for knowledge. Two people have a debate to have a better, deeper knowledge of their own respective ideas and belief. Socrates taught his pupils through debate, trying to prove someone wrong is not debating it is arguing. Kind of hard to take someone seriously if they cannot even fathom the medium they are using to express themselves is it?
Shamanism does not have any set, or at least not any uniformed, philosophical principle. Like every religion, it has to be taken by itself, not in comparison with anything else. Trying to compare two religion is like blindfolding two people and having them feel the same thing and then having them explain it. Like the story of the blind village and the elephant.
A belief in a religion requires faith, blind faith. We do not know what happens when we die, but we trust in our respective faith that what we were told in life would be true. Who knows if it is, nobody has lived to tell the tale, pun intended. Thus, it requires blind faith, trust that what we are being told about what happens when we die is true.
Jesus Christ, if he was real, taught that Christians should be accepting of other religions because he knows Christianity is not the only religion out there. He taught that one has to win converts over through goodwill and kindness, not ridicule and force. You, my friend, have stray too far from the correct path. Jesus would not approve.