The book was produced by the tradition. If the tradition is junk, then why would the book not be junk too?
This is one thing that atheists often get wrong about Catholicism. Catholics don’t believe sola scriptura, the Protestant principle that all Christian tradition is to be rooted in the text of the Bible. Thus, “Bible contradictions” and the like are not rebuttals to Catholic views the way they are to “fundamentalist” Protestant views.