Isn't it obvious? You're being protected against guns, bombs and knives. Boy Scouts with pen knives. People with wonky spectacles and screw drivers to fix them. Children with plastic swords. Suicide ice lolly lickers. Crazed cup of coffee holders. Mad old ladies with knitting. And crazy airline pilots with bombs in their shoes. Don't you feel safer?
Of course you're not being protected against jihadis because to single them out for scrutiny on the basis of their ethnicity would be racist and even worse than a terrorist attack.