Actually, there’s the whole “as Allah wills” thing in the Koran. Basically, some of the Islamicists believe that the wearing of armor is evidence of lack of faith in Allah - for if you are doing Allah’s will, surely Allah will protect you and none of the infidel bullets/knives/swords/arrows will hit you, right?
My ancestors had a *field day* with that particular idiocy when Islamic armies came against us.
Epic Fail.
The word some in your statement is very operative. We should not assume that all Islamic Terrorists in the future will never be wearing body armor. We should also not assume that their religion will universally forbid its use. The west eventually lost the Crusades. One of the reasons was that high end Islamic forces actually had better armor then the west. The Knights Templar and the Knights Hospitalier definitely had weaker armor then their Islamic counterparts. Then of course the Pope tried to forbid the use of the crossbow because it gave a simple peasant the ability to possibly kill a Noble Knight.