Agreed. However, how many muslims, whether "radical" or "moderate", acknowledge or recognize that the roots of their faith may lie with Arianism or Simon Magus?
The point being, Muhammed is the only figure for either of them to look to as the "Prophet" by which the measurable standard of a true Muslim should be compared. Both will confess this openly and without apology I assume. Therefore, those who best emulate the "prophet Muhammed" are the true believers and followers of Islam.
Who do we see doing that, "moderates" or "radicals"?