Sure. I had a bully when I was a kid. I do not go around putting people in acid buckets though to get back at the world. In fact, I do not go around even bullying people. This is the same idea that has turned Americans against cops. They shot a few African Americans in dangerous neighbor hoods wrongly, now lets go kill them! I assure you cops are not going out and killing for fun. Many like to do things like have jobs. 

Yeah pretty much this sort of "mistake" is going to be used as a PR tool by tools to paint the US as a villain when something like this happens, of course even reading the linked article and you'll see that

"Many Isil fighters are still holed up in the city, and are preventing thousands of civilians from leaving, effectively using them as human shields. "

So yeah... Sure the US did kill civilians, but they're civilians who are being held there by terrorists and used as human shields, to put all the blame of this on the US forces is really just weak minded. If you have terrorists who hold these children hostages to use them as shields... how do you try to paint them as the good guys here doing the right things?