You know the terrorists don't give a fig or a grape about Mecca. They operate under the cover of Islam, but they are not Muslim. Besides that, Muslims don't practice idolatry, so wouldn't be religiously attached to any particular place. They would be upset, probably annoyed, but they would continue on in their muslimhood. But keep making the suggestion; there may be a prize for the 100,000th who makes the suggestion.
Of course they are muslim. Why would you claim otherwise? Next you are going to claim that Sultan Suleyman was Budist or something. Face it, islam is a violent religion. It always has been, since mohamed himself
I'll bet you also doubt the effectiveness of the pigfat bomb.