The U.S. has done as bad, and worse, all along, for fourteen years, and will not prosecute itself and probably won't go after its proxy forces either.
FOX, CNN, PBS, and the rest of the alphabet stupes don't like to tell the public so, but the formerly-known-as-GWOT is and has been from the start a capital C crusade. It's considered to be a "holy" war - by those who started it and continue it, that is; and by that I mainly mean Americans.
Americans are the Good Guys, and are going after the Bad Guys. The Bad Guys all have the same BBC fake Russian/Middle Eastern/All-purpose accents, and are swarthy and like nothing better than to slice heads off.
Therefore, the Good Guys reason, the Bad Guys deserve a taste of their own medicine, only more so. After all, doesn't God approve of all of this- even the torture, even the murders of countless children and other non-fighters?
As we know, these are only some of the horrors put on to those people over there by the Western jihadists.
There is an old debate about ends and means. But if the Second Coming is thought to be the "ends", it is extremely easy to rationalize using any means available, with little thought of right and wrong.
Tactics don't matter to them as much as the overall strategy does. They believe the post-9/11 war they started in late 2001, -enabled by deception still successfully in place after all these years- is part of a long-sought fulfillment of Revelation.
The "Left Behind" series of books (and the computer game based on them) have the basic plot: the Christians kill Muslims for God, and so Jesus will come back.
As we have been told for so many years, jihadist fighters are the most brutal of all. The Anglo/American war against the Middle East is, among other things, a jihad.
This jihad styles itself as Christian, but is pre-Christian, operating on the" eye for an eye" law instead of the "love one another" law that sets true Christianity apart from pre-Christian Judaism.
I know all of that is far too simplistic, and that religion-inspired war fever in American leadership is not the whole story. But it is an important factor.
Chris Hedges has developed some of the same ideas with "American Fascists" stuff, which is worth checking out. He confirmed what I was already seeing in my own town and neighborhood church.
Of course it is nothing new, either. It's an old story, one of the oldest.
I mustn't forget to mention Bob Dylan's great song "With God on Our Side", which really says it all.