I can see why anyone who has not read the book would be befuddled by the movie. The French cook is rude, but that's a far cry from cutting off someone's leg so you can eat it. Are we supposed to believe that the carnivorous island existed? Are we suppose to believe that Pi is the son of a zookeeper? If so, how is it that he can't pronounce "orangatan"? My interpretation of the religious theme of the book is that since no one can prove that there is a purpose to his life or even any lasting consequence of it, each of us has a choice, to believe there is a purpose (God, if you will) or not. What Pi tells the owners of the freighter is that he has chosen the more plesasnt of the two possible stories.