I don't think they are.

The question is, out of a million swarthy, Arab appearing individuals and a million Anglo appearing individuals, which group would be significantly more likely to include a terrorist.

If you believe there is no difference, then you are correct to question any sort of profiling. If you concede that there is likely a significant difference and it is impractical to screen everyone equally, you should agree that appearance is a valid factor to screeners in the same way that a person wearing a tattoo saying "you will only take my weapon from my cold dead hand" might be as innocent as the driven snow but be of even greater interest than the swarthy male.

This does not mean that such individuals should be subjected to full body cavity searches but a bit more attention is warranted.

Those who believe that it is better that innocents perish to avoid any appearance of bias will not agree.