The central axiom of KJVO is that every English translation of the Bible has been corrupted except for the KJV. To back up this assumption, KJVO proponents present several central claims. I will try to briefly address these core ideas thought what is found here merely scratches the surface
Claim 1: Other translations attempt to water down important doctrinesThere are plenty of websites that list out all of these supposed compromises, and it would take hours to address each one, but the most glaring error of this attack on more recent versions is that it compares English translations with little consideration for the wording of the original languages. This is why you will rarely find an actual Greek or Hebrew scholar that supports KJVO. It is simply a rookie mistake to think that you can address the accuracy of a translation from a Greek or Hebrew passage by comparing English versions.
Claim 2: Other translations leave out passages of ScriptureThis is not an entirely accurate claim, since most recent English translations don't completely leave out passages. There are, however, a few select sections of Scripture that appear to be missing from the earliest and most reliable manuscripts and as such, they are commonly annotated with a phrase such as "Some of the earliest manuscripts do not include..." or sometimes the questionable passage will be listed in the footnotes. There is an ongoing debate over these verses, but the fact that they are identified shows that the translators want to be as accurate as possible. This is more accurate and upfront than simply including a verse in the English version because tradition says it should be there, even if manuscript evidence is sketchy. None of these questionable passages invalidate a core doctrine of Scripture that is established well by other unquestionably accurate passages.
Claim 3: The KJV is based upon better source manuscriptsThis is one of the more preposterous claims of KJVO. In fact, the opposite is true. For example, the KJV and other Reformation period translations were based upon versions of the Textus Receptus ((a Greek edition of the New Testament assembled from incomplete manuscripts)) edited by Erasmus. Erasmus had only six Greek manuscripts to work from, and none of them were complete. (He actually translated a portion of the NT from the Latin Vulgate back into Greek so that he would have a complete work) By comparison, we now have thousands of New Testament manuscripts many of which are older and more reliable. (This is not an arbitrary claim. Through the science of textual criticism, modern translators have gone to great lengths to develop reliable methods of determining which manuscripts are the most reliable.)
Claim 4: Modern translations have been corrupted by the personal bias and spiritual inadequacies of their translatorsThis is simply an ad hominem fallacy, and if it were true would affect the KJV just as much as it would any other English translation. There is no denying that the personal biases of translators will have an effect on how they approach a passage of Scripture. That is why most reputable translations are created by a team of translators that can prevent any one person's bias from affecting the final work. KJVO adherents take it a step further and assemble elaborate conspiracy theories about how modern translations have been corrupted by everyone from Roman Catholics (Keep in mind that the KJV was translated by the Church of England, not evangelical Christians, and in fact the translators specifically translated certain passages to fit with Anglican teachings about the church and baptism) to Satanists. These approaches are not designed to be rationally compelling, but are, like many conspiracy theories, designed to play on the fear and angst of others. To anyone who has actually studied Greek or Hebrew, and can compare the original languages with modern translations it is abundantly clear that no such corruption has taken place.
Claim 5: The Methods of Textual Criticism are flawedTextual Criticism (Not to be confused with types of "higher criticism" such as form, source, redaction, etc. These methods are based on many improper assumptions.) is the science by which experts take various Greek and Hebrew manuscripts and compare their variant readings and try to determine what the original author wrote. It is certainly not foolproof, but it is the most accurate method available for determining what the original writers of the Bible put down on paper. The interesting thing is that the editions of the Textus Receptus which were used in the translation of the KJV, were created by men such as Theodore Beza who was a pioneer of this science. Yes, you heard correctly. The KJV is based upon the science (then in its infancy) of Textual Criticism. So, if the very use of this methodology has corrupted modern translations we must logically assume that the KJV is corrupt as well.
Claim 6: If you truly believe in the infallibility of Scripture, you would be KJV onlyFundamentally, this is an argument based in fear. Many of us grew up in a world where "the Bible" meant the KJV. We got used to the "thees" and "thou's." It is easier to simply accept the one translation as the word of God, than to be thrust into a word where there are literally hundreds of English translations that must be evaluated for their merits. The solution? Create a doctrine that claims that the KJV is the only inspired word of God in the English language. Usually, this doctrine is established through clever rhetorical methods by asking loaded questions such as, "Do you truly believe that God can preserve his Word in an infallible form?" Of course, every Christian is going to answer in the affirmative, but this is simply a bait and switch. The question is not "can" God do something, but what did He do? The reality is that you run into some very difficult territory when you start claiming that any translation from the original language is infallible. Anyone that is familiar with translation knows that information is lost when you translate it into a different language. Even if we had the original manuscript in front of us, there is no way that a translation could be considered infallible and perfect. That is not the way that language works. The only way that you can have an infallible and perfect translation is if God inspired the translators in the same way that he inspired the original authors. So to claim that the KJV is the inspired, infallible word of God is to claim that God inspired the translators as he did the original authors. That belief is heresy by the standards of almost all Christians who hold that the Canon of Scripture was closed sometime soon after the twelve apostles died.
This is a sort of last resort argument for KJVO. To be sure, there is always a tension between rendering a passage as close as possible to the original language, and rendering in a way that is readable by contemporary standards. (I will readily agree that certain translations are useful for certain things. For in-depth Bible study, I would never choose a version that uses paraphrases and that strays significantly from the actual wording of the text in its original language) What is certain is that the KJV uses horribly outdated language. I have heard some KJVO adherents brag about how their young children can read and understand the KJV, but there is a reason that we don't write first grade textbooks in Shakespearean English. We want children to understand them. As a child who grew up in a home that primarily used the KJV (though my parents are not KJV only and encouraged me when I moved to more updated versions), I can say that there are whole passages that never came alive until I read them in a language that I was used to reading and understanding. The truth is that the writers of Bible used language that was common to the audience, because they wanted to be understood. The New Testament uses Koine Greek, the language of the common man and not simply of scholars. Remember that one of the cornerstones of the Reformation was the availability of God's word in everyday language. Why would we saddle our children with a Bible written in a language that hasn't been used for hundreds of years?
Claim 7: Modern translations use language that is too ordinary and does not respect the integrity of God's word.
This is a brief summary of some of the greatest issues with KJVO. Why though, should we take the time to address this issue? Is it really our concern if certain churches want to stick with the KJV? The problem is not so much that, as it is that this has become a divisive factor, and a point from which some can claim spiritual superiority over others. As a missionary kid, I can even remember my parents getting a letter from a person ending their support because we used translations other that the KJV. Really?! In a country where most people speak English as a second language, or not at all? Do we really want to require them to learn Old English to be able to understand the Bible? That is simply ludicrous. Like many other fringe doctrines that have wormed their way into the church, KJVO is a distraction. It's a way to consume the energy and resources of the church with meaningless pursuits.
With all of the genuine challenges that face the church in today's world, it's time to commit KJVO to the dusty recesses of history where it belongs and move on important issues. If by any chance, you are a KJVO person that has made it this far down the page, I will not question your motives, but I implore you to allow truth and Biblical reason to win out over feelings of piety and fear of change. There is way too much at stake - a world in need of a Saviour, and a church in desperate need of rejuvenation.