The movie makers have the right to destroy Mecca if they want to. He could even make a movie which only destroys Mecca.
It's wrong for any Muslims to commit violence in response if they do, and for there to be a threat of that which causes a chilling effect on the director's decision.
However, there's also a real history of violence based on US policies, and an ongoing political tension (bomb bomb bomb Iran, McCain said), where it can be a good choice to avoid fueling the passions for war against Muslims, providing a fantasy movie for the people who would want such a war, just as we frown on a movie that admiringly portrays the assassination of a sitting president that could encourage the real thing to happen.
Those who condemn the director for backing off for the wrong reason can also praise the decision being good for other reasons, not just promote 'war porn'.
A movie *could* be made for pedophiles which shows the fantasy of men having relations where the children greatly enjoy it, and include in the stories ways the men can get away with it, and it would be widely condemned as 'offensive' if not 'dangerous'. That movie is probably best not made, even though it can be.
A movie *could* be made using cartoon or special effects of a puppy being viciously tortured for hours (or the real thing filmed in some countries).
'Can be' doesn't mean 'should be'.
We have slightly different standards for some racial statements because of the real history of prejudice againdt blacks, where we might say a comment or joke about a white person is 'just humor' where about a black it's offensive. Thwre's a good reason for that.
We might do well to have a double standard for Christian and Muslims in this fantasy movie violence as well, not because of the threat of violence, which is wrong, but because Christian movie goers can watch the fantasy destruction of their own places as pure movie fantasy, while the fantasy destruction of Mecca might be more of stirring the support for violence and way in some people, and best avoided.
Would you make a movie in Israel that shows some crazy dictator coming to power who does a holocaust against pretty much everyone, including scenes clearly of Jewish communities being gassed as well as scenes for other groups, and say there should be no distinction just because of Jewish sensitivity to the real holocaust? Would it be ok to release that same movie in German, if it gets a following among neo-nazis just for the Jewish parts?
West Germany has free speech - mostly. The Nazi symbol can't be used in things there generally - because of the real history, if not the simmering neo-nazi support.
I'm not suggesting such a limitation on free speech under the law here, but I see no problem with some editorial discretion because of the real war tensions.