While I definitely consider TT a jerk, his choice of words in no way contradicts the standard English language the way it is defined in modern use or dictionaries.
But since there are many people who think that they can hurt a few dead terrorists by maiming their own language, I have a compromise for you:
There are many millions muslim fundamentalists who wish us ill and they all believe in paradise and virgins. Nevertheless very few act.
Would you mind if I say those who just sympathise with terrostist or help them (with money, etc.) are prevented by fear from acting violently. I think you would not mind if I use the term "fear" or "cowards" describing US-hatine muslim fundamentalists.
Would a sentence "The terrosists are less cowardly then their supporters" offend your feelings?
Regardless their academic merit, "bravery" or better yet "fearlessness" are quite good for practical purposes.
When setting an ambush at an afghan mountain trail against an approaching caravan of four dosen mujaheddin the captan probably though like this:
"Two mashineguns in that ravine would have been enough to pin down that bunch if they were germans or americans and keep them in place for mortar fire, but since those mujaheddin are much more fearless, they will charge - so five machineguns are needed to cut them down before they close to grenade range".
What did TT mean by his bravery remark? If he ment that we should beware of those terrorists, I agree with him. I doubt he ment that we should admire them.
easymo: The comparison with the robbers is not appropriate.
There is a difference about the bank robbers and other violent criminals in America compared to the real evil terrorists. Most of them are on a stupid side and they fail to assess risks correctly or exercise the proper foresight. Their "work" is dangerous but they engage in it not because they lack fear but because they fail to correctly estimate the odds - just like americans who play lottery.
Whatever else the terroststs were, they were not stupid and they correctly estimated the odds of their death as 100%.
miko