Don't get me wrong. I'm calling for a war against Iran at least since 20 years... and now more than ever.
I also see no other realistic alternative to a war. But a war does not equal genocide.
We didn't kill all Iraqis, Afghans, Vietnamese, Koreans, Japanese or Germans. Defeating the enemy has priority and a total war as waged against Japan and Germany has it's merits.
But once defeated we tried (successfully) to turn their societies into free, democratic and capitalistic ones. That's what makes the USA so special.
If (and it's pretty likely) a war against Iran is coming, we will bomb and destroy their WMD, military and petro-chemical infrastructure. We will kill their leadership and their agents. Civilians will die... This is part of war's reality but certainly worth if the Islamic Regime of Iran can be crushed.
I agree, Iran needs to be dealt with and soon, the free world simply cannot let them develop WMD. With every passing day they get a little closer to their goal and we get a little less willing to fight them.