There is a necessary asymmetry here that can be illustrated by your comment. They believe their God and yours are the same; you don't. In other words, you reject the very foundation of their combat with the west. It is well that you do.
Fundamentalist Islamics call it a religious war, but our politicians have understood the dangers in letting the enemy define the battle lines.
They say they have the true religion; we fight for the right to make that determination as individuals. I'll take this one step further, and it's a profound distinction: devout Christians believe that Christ will bring his kingdom to earth as he unfolds his plan for humanity. Humans simply must choose to believe in Christ to be saved. But fundamentalist Muslims believe that they should fight wars to bring about God's plan. Think about it: Christians trust God to bring heaven to earth; Muslim extremists think that mass murder is required to bring it about.
A hadith discussing the end times, in which Muslims will fight nonbelievers to trigger the onset of Judgement day reads as follows:
Allah's Apostle said, "You (i.e. Muslims) will fight wi the Jews till some of them will hide behind stones. The stones will (betray them) saying, 'O 'Abdullah (i.e. slave of Allah)! There is a Jew hiding behind me; so kill him.'"In other words, in this militant view of Islam, Muslims are to actually play a role in their God's plan by killing people who don't believe, especially Jews. Not all Muslims believe this, by the way.
The reason we refuse to call this a holy war is that we are beyond the concept as a civilization. Think about that! The Christian God does not need humans to fight wars for his name. But Americans of all creds will fight for our right to choose our own beliefs as individuals, and we will fight for others' rights to do the same.