To be KJVO means that the KJV is the inspired infallible Word of God. They don't take that position.
This seems to be a BB definition. I've seen it as a sticky in the Translations/Versions page.
They are simply KJV preferred. I think you need to do more study on this subject. There are many on this board that are not KJVO, but at the same time reject most modern versions based on the text that they were translated from. That is a different issue.
I'm well aware of the textual differences. IMO, rejecting every version except the KJV is, by definition, King James Only. It doesn't matter the reasoning behind the policy. I think you are making a distinction without a difference.