It is very easy to say this group or that group committed the atrocity
when we do that we throw a blanket over everyone else in that group. When we throw an idealistic blanket over a group we stop seeing them as individual people. When we stop seeing them as individual people it becomes psychologically easier to do bad things to them because we are not harming people but a group(Insert whatever group label you want)

The truth is if you, I or anyone else takes any action that injures or ends a life then they are responsible for that death or injury.