Why do almost all fundamentalist Christians prefer to use the KJV bible?
The simple answer is tradition and misinformation. Many fundamentalists use the KJV because they believe that is the best and most accurate option. However, if you stop and look at the best manuscript evidence that we have today, you will quickly see that the KJV is not the greatest. The KJV was the version specially commissioned for King James in the 1600s. Since that time, many more manuscripts have been found and versions that were not tailored to just one person or denomination have been created. The best versions are those which involve a broad range of experts from various traditions. That helps the translation to be less skewed toward a particular viewpoint or ideology.