I will be honest with you, I am not sure how I feel about this. A global clash of civilizations would be utterly horrific, and would probably dwarf both World Wars in terms of body count. On the other hand, the defeat of a fundamentalist belief system would probably mean a long-term gain for all humanity.
And once you've nuked Arabia back to the stone age and (somehow) conquered the rest of the Muslim world, what do you intend to do? The only thing you will have managed to do against Islam at this point is to push its followers further towards misery, reclusion, violence and extremism. As history tells us, in order to truly eradicate an entire religion, you will have to use some combination of religious oppression, proselytizing and genocide. So much for the "greater good".
I think the goal of any sort of wide-ranging Mongol-style conquest of the Islamic world is foolhardy at best, genocidal at worst. While I would like nothing better than to see violent Islam consigned to the ash heap of history, I don't believe that military action would accomplish this end. Frankly, that should really be the last resort. War doesn't prove whose ideology is correct, it only shows who is militarily stronger. The right combination of scientific & historical education, economic development, and good old-fashioned propaganda, on the other hand, might work.
Sure, you won't be defeating fundamentalism so much as displacing it. And, of course, you will be the first to try and apply those methods to a belief system with one billion plus followers. But, hey, if you really wish to become the greatest monster in the history of mankind, go ahead.
Hey, I never said I was fully on board with the agenda described in the OP. Besides, who one considers a "monster" largely depends on what side of history one is on. Romanians don't consider Vlad Tepes a monster. The Uzbeks don't consider Tamerlane a monster. Mongols don't consider Genghis Khan a monster. The Iranians don't consider the conquering Achaemenid kings (Cyrus, Darius, Xerxes) monsters. Most Western civilizations don't consider Caesar and Alexander the Great monsters. I'm sure that if the Hunnic Empire had survived, Attila would be hailed as a national hero there.
Also, why stop at Mecca and Medina? How can you condemn them, and yet spare Rome and Jerusalem, the embodiments of the two absolute worst aspects of organized religion : its corrupt leadership, and its ability to spread hatred among people?
You'll get no arguments from me on that point. The only differences are that 1) right now, the West is not in conflict with the Vatican or with Judaism, and 2) neither of these religions has the sort of expansionist doctrines that Islam has (at least, not in the present day).
That's also mainstream Christian belief about the Bible. And mainstream Jewish belief about the Torah. Etc etc etc.
Well, not quite. Muslims believe that their holy book was literally dictated by God to Muhammad, while Christians only believe that theirs was divinely inspired by Him. Whether this fundamental difference in theology justifies the eradication of Muslims is up to you to decide.
This is basically what I meant. Biblical literalism is a fairly recent innovation in Christianity. Quranic literalism has been a feature of (most) of the surviving sects of Islam, though some are a bit more "serious" about it than others. This alone is hardly justification for genocide, and I am not arguing that it is. Using one's own religious doctrine as an excuse for violence and subjugation of others, however, is quite another matter, and it needs to end, one way or another. I would rather it end with some sort of peaceful coexistence. Whether or not that happens, time will tell.