Too imperfect for this one to have been written by the hand of God.
Nobody is claiming this is the original. It is just the earliest known copy carved in stone. According to the article, it is from Roman times. Also, it is not even an accurate copy of the Ten Commandments as they appear in the Hebrew Bible; it is the Samaritan's version, which swaps out one of the Biblical commandments for one the Samaritans believed in.