Exactly. Me either. Consider that they obviously felt that the center of Iraq was no longer safe for them to take over, they are perched within "running distance" of the Syrian border.
I hope we do this right, that is, I hope we are willing to continue killing them EVEN AFTER THEY CROSS OVER INTO SYRIA.
Assad has done nothing we asked him to do, if we engage the Syrian army, then so be it. There must be consequences to Assad for not listening, and this is our opportunity.
As for Syria, I have long thought our forces need to eventually turn left for Syria, and right for Iran. No sign we are being that aggressive yet.