Religion is what motivates them they are called right wing christian extremists.
Like you missed that?
Is Christianity responsible for their evil actions?
Their embrace of christianity in the extreme sense is responsible for their actions.
I am not sure what you are trying to get at the same is the case with any extremist who has extreme views regarding religion this is not isolated to Christianity or Islam there are Hindu fundamentalists and extremists also.
What is your point Kszama?
My point is that if you are not willing to hold Christianity responsible for Christians' evil actions, you cannot hold Islam responsible for Muslims; evil actions. To do so would be hypocritical. To remain fair, you would have to hold that Muslims' evil acts are because of their extreme view of Islam just like Christians' evil acts are because of their extreme view of Christianity. Any position other than that is as mentioned earlier hypocritical. I don't mean you here.