From what I've heard, this airstrike took place about 5km from the nearest US base, which seems like a reason to be optimistic if it's accurate. An accurate airstrike is impressive, I'm sure, but if an airstrike is the pentagon's best option within walking distance of a base, then perhaps they're not in shape to start a real war... and they have enough analysts to say so.
It is the least dangerous for American lives. Soldiers on the field can die. A UAV pilot can die from PTSD or whatever (as can soldiers), but not directly from taking part in the strike.
Let me put it differently. If a military force thinks sending soldiers even as little as 5km out from the base is best avoided, that military force is not in shape to start a war. The Pentagon has analysts enough to say so.
https://news.ycombinator.com/item?id=21942965
https://news.ycombinator.com/item?id=21942853
Presumably people are concerned because this may be the beginning of war.