How to Argue with the Revisionist Historians

It's actually far simpler than you would imagine. Rather than bogging down in an endless battle of quotations, theories, facts, and obscure references, just keep them honest with their language. For example, if they want to say that Western Christianity has killed more people than anyone else in the world put together, just insist that we also get credit for all the good things in Western culture as well. In otherwords, they can't take Voltaire as their hero, and give us Frederick the Great (an atheist) in order to blame us for European religious wars. Just ask them to be consistent. If they make sweeping generalizations about "the Dark Ages" and "the Church" and burning heretics, crusades, etc., then they should have no problem with a sweeping generalization like "well, Protestant America has repented of the sins she never committed and cleaned up all of Christendom's past mistakes". If they have their myth about the Dark Ages, then we should be allowed our myth about the Modern Dark Age. It's that simple.