I always thought
that our "home-grown" nutcases usually have an ax to grind. Be it Ruby Ridge or the Unabomber's anti-tech spiels, the Weathermen, etc. Local boys probably wouldn't want their "message" confused with the "message" of an Islamic fanatic.
Unless it was a total whack-job who was deliberately trying to foment full-scale war with the Arabs. Doubt it, though.
