Threats to destroy Meca or a religious site in Mecca may feel good. First, all evidence suggests Muslims become more violent and radicalized when a mosque is attacked. Second, there is zero chance the US is going to launch a religion based war. Third, it would be counterproductive to enrage every Muslim country that is fighting with us or is neutral (Afghanistan, Iraq, Kuwait, Pakistan, ....it’s a long list). Fourth, strong repression of a religion can lead to its spread (Christianity).
Nuclear weapons are a game changer however...I agree with your points. But if a city is nuked in the U.S. then let me say this...we will use nukes in response. I suspect that our troops would be bugged out of Afghanistan and the mountains of Tora Bora would be nuked into oblivion. I also suspect that you won’t see feel good investigations and polls about waterboarding since the American people will be polling about 95% in favor of any and all response back.
You are absolutely right. Destroying Mecca may give us a warm, fuzzy feeling inside, but it would launch a worldwide religious war against billions of muslims, a war the West simply isn’t willing to fight right now. Hell, even right after 9/11 we had people warning against striking back.
How about if New York and DC are taken out my Islamic WMD’s? Would you hit Mecca then?