“we need to make an example out of a few million of these a-holes”
I understand your feeling, but we have moved very far from a policy of wiping out civilians populations on that scale.
Realistically, I could only see that happening as a counterstrike to a serious WMD strike against us. As a counterstrike though, many target packages could be considered, but few politicians would dare to use them. I especially doubt that Obama would launch much of a counterstrike, much less a first strike.
Having a conventional bloodbath between Sunnis and Shia has the effect that they both lose to a significant degree. We can leave them to punch it out between themselves for a while.
Unfortunately, we do need to return to that policy - because that is the only way militant political Islam will ever be defeated. We need to become more vicious, more ruthless than our enemy. We need to make it so bad for them that the mere thought of us will throw them into a paralyzing panic.