Why?
Because of Revelation 22:18,19
18. For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book:
19. And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book.
So my first question was: The King James version is a translation, so it had to be changed at some point. No translations are perfect!
Their responses to the question ranged from: King James didn't experience those plagues, he must have translated it correctly, ... to the King James version is the first one translated into English and since The Living Bible or another version is different, then King James must be right as the change happened between the time of the King James and the subsequent translations.