This is a very sad thing:

Here is a headline:

U.S. Strikes Hit Rebel Group in Syria; Civilians Reportedly Killed 

The sadness has to do with the collateral killing of civilians; and by the code of Pushtunwali, it just drives the Islamist Jihadist way beyond their semantic threshold of REVENGE.
Here is the news item for the above headline:
U.S. airstrikes have reportedly hit a compound belonging to the Islamist rebel group Ahrar al-Sham, one of the top groups fighting Syrian President Bashar al-Assad. The strikes came as the U.S. targeted the al-Qaeda-linked Nusra Front. On Thursday, Ahrar al-Sham said the strikes destroyed one of its bases and killed civilians including children. An unnamed Pentagon official told The Wall Street Journal the group was not targeted intentionally. Speaking Thursday, Chair of the Joint Chiefs of Staff General Martin Dempsey compared the fight against the Islamic State in Syria to a Rubik’s Cube.

General Martin Dempsey: "North of Aleppo right now is just almost — it’s a Rubik’s Cube, frankly. And the more you try — it’s like the Heisenberg principle: Every time you touch it, it changes, and you have something new to consider. So, this is a case of staying true to the principle that we will over time defeat ISIL."

A compound is not a military target. There will be civilians and their children.

For the cognoscenti, it is obvious that General Dempsey's "WORDS ARE FOR THE WINDS". This phrase "words are for the wind" was first created by George R. R. Martin, author of the Game of Thrones.