Isnt it a warcrime to shoot unarmed citizens not in uniform.?

It is if it is intentional. In the case of terrorists, they are fair game and if they choose to hide behind innocent civilians then the blood should be on their hands, not the hands of the service members trying to take out the bad guys. More civilians have been killed on purpose by terrorists than were killed by accident by US troops in this conflict. Maybe if Syria actually guarded their borders more then it wouldn't have got to the point that we had to bomb a area on Syrian soil to get the bad guys.