First Asma Khalid explained why she rejects the label "moderate Muslim" (at Christian Science Monitor, then at Alternet). Applied to Muslims who reject terrorism, the phrase seems to imply that "Osama bin Laden and Co. must represent the pinnacle of orthodoxy," that "suicide bombing is a religious obligation for the orthodox faithful," something that "moderates" have fallen away from.
Then Lindsay Beyerstein of Majikthise chimes in with the more general point that claims of "moderation" and "orthodoxy" can't be taken at face value in any situation. Why should UCC members be called "moderate Christians," as if they were watered-down alumni of Moody Bible Institute? "Claims of fundamentalism or orthodoxy are positioning statements for brands. We often treat claims of religious orthodoxy as if they were statements of fact rather than rhetorical devices. Positioning your doctrine as the orthodoxy is a way to marginalize your competition. If we uncritically allow the most reactionary sects to claim the mantle of orthodoxy, we do the work of fundamentalists for them."
Khalid says, too simply, that "True orthodoxy is simply the attempt to adhere piously to a religion's tenets." But it is rarely obvious what those tenets are, or, more precisely, which ones are considered operative at any given time. I can't say whether Khalid or Osama is the more accurate interpreter of Islam, but I do know that both warmongers and pacifists believe they're following Jesus.
In normal usage, "orthodox" pretty much signals "conservative" or "fundamentalist." Anyone willing to apply that word to themselves probably doesn't believe what many more liberal Christians do, that their religion's tenets evolve over time and will continue to do so. For those folks there is neither orthodox nor unorthodox, but simply more or less evolved. (Correct me at will.)
It would be nice to think that Osama and Pat Robertson were unorthodox representatives of their faiths, but I don't think it can be assumed. It has to be checked out. The mantle of orthodoxy is not necessarily the property of those whose opinions we agree with.