Because it is not the original, because it has been tamnpered with, changed, added, deleated, redacted, stitched together, etc. by various individuals and is a human product.
The Bible is covered with God's fingerprints.
Boy you sound like a Mormon.
1 Nephi 13:28
28 Wherefore, thou seest that after the book hath gone forth through the hands of the great and abominable church, that there are many plain and precious things taken away from the book, which is the book of the Lamb of God.
1 Nephi 13:29
29 And after these plain and precious things were taken away it goeth forth unto all the nations of the Gentiles; and after it goeth forth unto all the nations of the Gentiles, yea, even across the many waters which thou hast seen with the Gentiles which have gone forth out of captivity, thou seest--because of the many plain and precious things which have been taken out of the book, which were plain unto the understanding of the children of men, according to the plainness which is in the Lamb of God--because of these things which are taken away out of the gospel of the Lamb, an exceedingly great many do stumble, yea, insomuch that Satan hath great power over them.