I'm just going to point out how you left out Arabs crimes against the Iranians and their own people to show how biased you truly are in favour of a certain sect of Islam.
Not sure if that is case with this user..but
The problem with that phenomenon is ingrained with the East vs West divide..
the isolationist ideals work on the "iron-curtain" philosophy instead of a Strong,vibrant and evolving culture/image.
The fact is that brutality has no region nor religion... and is simply genetic and socially inherent to Humans(Even Gene Roddenberry could not wipe it out completely)...That being said..
the identification and condemnation of it is not uniform..
Ill give you an example,
My family was living in Saudi Arabia within the Al-Hamra compound during the bombings in 2003
Riyadh compound bombings - Wikipedia, the free encyclopedia
Explosions, people dead.. etc.
However, when the Firing started.. and the windows flew.. my Father.. along with the rest of us were generally very calm and controlled about it..not that there was not fear or panic but we knew how to handle it..i.e.. knew which room would best protect us.. etc
In contrast.. the rest of the people panicked and lost their lives.
When we returned to our House after a month or two at a reunion.. Most of the people still felt shaken, shocked.. and vowed never to live there again.. while we quite the opposite and upbeat and suggested that we live on as to give a message.
Why? We arent superhuman nor courageous heroes.. but simply because we hail from a city where the gunfire was/is common and the sound of an AK-47 is not alien due to criminal activites or sectarian violence which we all knew as commonplace. .. Where the loss of life is in such constant cycle that you slowly become immune to it.
Hence you dont panic..when you hear of a mutilated body and generally wont film it, or care about it.
So.. where such brutality is common there will be less of a reaction and vice versa.
Now the second factor is the general frsutraton of the people at better lifestyles and better lives....
for eg.. If I have an accident with another car back home Ill probably settle it after a few hot words and there wont be any police report.
However, if the same happens with a motorcycle rider.. then its likely going to be a public outrage sending me into a guilt trip.. there will be support for the bike rider due to his less expensive ride and "poor" status as compared to my air-conditioned compartment ride.The more expensive the car.. the more comments and notions of ill-acquired wealth will be thrown in( a taxi driver will face less heat than someone in a BMW).
Now take that psychology and add to it the impression that the west has ill-treated Muslims in their lands.. occupied them.. and you will see why the west is the BMW rider and a mutilation by a US soldier suffering from PTSD or otherwise will garner greater hue and cry from the public as compared to a sectarian motive mutilation.
The same way.. a rich man dying(the west) will be taken as justice served on a by-default branded exploitative image.. as compared to a poor man dying who will be hailed as the unnamed forgotten unjust death.