Rules are not an Appeal to Authority. It isn't a claim that it's right because it was said by an authority without further evidence. The rules themselves are evidence that things are done that way. Now, if I had said that clerics are played a certain way, because Gary Gygax said so, that would be an Appeal to Authority.
Fair enough. To be clear, it felt as though I was appealing to authority, and I was claiming my own argument was weakened. Thanks for the fair play.