You are going in a more PC direction than I am. The point is that modern day international terrorists are almost all Arab, South Asian, North African. So of course if Terrorists hijack a plane somewhere in Europe or America you are going to focus the investigation on the people that have links to those parts of world.
The terrorist "can" be anybody, but in all probability it won't be your gay German Barber. It''ll probably be a Muhammed Hassan, or Ahmed Hussien. Of course it'll be a slippery slope to screen them by race, but it is worth it if it saves the lives of scores of innocent people.