"Them": Those who would forcibly attack or threaten others so as to impose their beliefs as the only ones allowed in the public sphere, and those who would fight to retain that power.
If a "kill 'em all" battle begins, those mystical, mythical "Moderate Muslims" have the same choice as the rest of us: fight for those who want to impose Islam as the superior faith, fight for those who oppose such subjugation, or sit quietly on the sidelines and pray (to whomever you wish) that the bullets and bombs don't come your way.
The tough part is figuring out who is on which team, especially since they're making asymmetrial warfare an art form... honesty, bravery in the field, targeting only enemy combatants, fighting in plain uniform to avoid loss of innocent life, etc. are all going to be taken off the table for this one, for at least one side... and I don't see "our" side maintaining it's more righteous positions on those matters for too many years if the battle is at all unsure.
I can agree with your definition. The problem is that they're trying to kill my family. They can believe anything they wish and I couldn't care less. Once their beliefs cross the line into action, the gloves come off.
I would also suggest that we may have to provide moderate Muslims with an incentive to fight against their radical brothers. The best incentive I can think of is to point out that those fighting on our side are a lot less likely to be mistaken for the enemy.