But then, denying that there are neocons looks a lot like a way of saying that one doesn't have an argument.
"Neocon" has become a way of saying "Middle East war hawk." It may not be the best, most exact, and most descriptive term, but to dismiss an argument because one's opponents terminology isn't pleasing or isn't the best, is to duck a controversy.
If you're on the inside of some tendency you can deny all terms to categorize your position. It's just common sense, what anybody would believe. But people who disagree are going to try to find a way to categorize your position. For them it isn't common sense or the unavoidable conclusion of all rational people. If their terms aren't the best, it doesn't follow that you've won.
The problem is, whatever the term may have meant once upon a time, it is now used as a general pejorative for anyone whom the author disagrees with (as long as the target is even marginally perceived as a conservative and/or a Republican). Since the term has really lost its meaning through corruption in common usage, I have no problem discarding it.
Going back to Godwin’s law, it does not deny that Hitler or the Nazis exist, it’s just recognizes the cheap and lazy tactic of calling your opponent a “Nazi” or comparing them to Hitler, especially when there are better comparisons to use.