Knowing intent is one of the hardest things to do. War and criminal courts are also widely different. The very same action taken in Iraq can get you a medal, in Vermont would make you a monster.
We can obviously see a lack of concern in the way Assad drops bombs. No guidance systems means he can't intend to hit anything, he just drops them on rebel areas. Dumb bombs hit without precision. Our bombs however are guided. We watch our targets for days for a perfect opportunity.
We've also bombed weddings.
I wouldn't compare Americas actions to those of Isis. They intentionally target innocents with zero military value. I wouldn't differentiate too much between Assad and America however, we just have smarter weapons and our backs aren't to the wall. If America was loosing a war like Assad, our brutality would also be exposed. Ask Dresden or Tokyo how America bombs. Or Saigon. Or Mosul. Or Fallujah. Even we sometimes target areas where we know for sure, we will kill innocents.