Virtually any religion can be used to justify almost anything. The religious ethic of turning the other cheek didn't stop Christianity from being used to rationalise slavery and other atrocities. People of the same cultural background as the offender who disapprove of his actions don't share joint responsibility for the killings. That applies whether it's an Anglo Saxon from a notionally Christian background as in this instance, or a Muslim who commits the atrocity as has happened elsewhere.
