At issue is the reliability of the texts, not some nefarious personal agenda. It must be understood that the proportion of the Greek New Testament about which there is agreement among the texts is astonishingly large, while the number of seriously disputed passages is surprisingly few. In addition to these textual considerations, KJV Only advocates also fail to appreciate the fact that, by definition, no translation is ever final. English is a living language. Living languages change.
Words take on new meanings or fall into disuse.
Modern translations use contemporary English to relay the meaning of the original Greek and Hebrew. Moreover, no translation is perfect. Translators are human. All translations contain errors. The King James translators were human.