And, there is a LOT going on (thankfully most here don't know about it), but you have to play the percentages. The percentages say that the profile I described above is most likely to be the bad guy. Ergo, that's who you profile.
That's why they call it profiling. Serial Killers are most likely early middle aged white guys. That's who the police sort of kind of start off looking for.
This isn't lost on AQ, either. I would bet you good money they are really working to gather up some trustworthy non-arab appearing operatives. Take a look at your prison populations. There are some pretty ornery muslims there.
But, that isn't the immediate problem, until evidence gets produced to support it.