Honor killings are extra-judicial killings, and are therefore murder. They are not permitted in any society, Islamic or otherwise. As I have already pointed out, such killings have nothing to do with Islam, just as "bride burnings" have nothing to do with Hinduism. The victims are almost always women, who are killed (or mutilated) because they have failed to live up to the expectations of the family, clan, or tribe, by having a secret boyfriend, refusing to accept an arranged marriage, or failing to please a demanding mother-in-law.
Different interpretations of the Qur'an rarely lead to conflict. Not even the Sunni-Shia divide arose as a result of doctrinal disagreements. It was a political dispute over who should succeed the Prophet that led to the split. The Shias maintained the succession should stay in the family, which is why, to this day, they call themselves "Ahl al-Bayt" ("People of the House").
The Muslim belief is that all people are born Muslim, but sometimes adopt other beliefs because of their upbringing. That is why non-Muslims who embrace Islam often refer to themselves as "reverts", rather than as "converts". Muslims, with the exception of takfiris, are generally well-disposed towards non-Muslims, except when they perceive the latter to be hostile.
But all this is beside the point. I didn't come here to debate Islam. Anyone who wants to learn about Islam can read a few books, or take an Islamic studies course at a university. I came here to try to persuade people to research the Christchurch "shootings", rather than blindly accept the official narrative of events. You have to understand that Christchurch was staged, and staged for a number of political reasons.