The hell are you talking about, allied bombings killing civilians is highly scrutinized even with the mistake is genuine and anyone can make it.
Also there is a difference in targeting that makes an action terrorism or not. In war you ARE going to kill civilians, there is no "ifs" about it, it is going to happen. The only difference is if you are trying to minimize it to the best of your ability (lack of intel is the most caused reason for civilian casualties), saying fuck it (Russia, Syria, and Saudis), or outright targeting the civilians (terrorists).
Not sure about other countries, but you can talk to actual soldiers in U.S who were denied air support because civilians were in the area or when strikes are canceled because of civilians in area. There is no "both sides" to this coin and this is like one of the only areas where Neogaf is too damn liberal and use that argument while playing arm chair general.
Yes, we can scrutinize these actions, but posts like "we just created more terrorist" and "How are we different from terrorist?" and posts that says "they should be 100% certain civilians aren't in the area" is really annoying to read.
Yes intel was lacked on this scenario, but outside of assaulting the building (which we don't know if they could, since snipers can snipe people from much further away while switching windows etc.). You got someone on this thread saying, "why didn't they snipe the snipers?" as if that is an easy task with many windows/kill holes a sniper can use. You would also need to find the perfect vantage point (which we don't know if they had), and hope they don't spot you going to it. They chose to bomb the sniper nest and unfortunately, it had 200+ civilians in it with ordnance in the building as well.
That is a fault of IS as a soldier should not be using a building civilians are in as an encampment.