Christian non-violence is very easily explained: "Thou shalt not kill". Jesus wasn't kidding about all that "hippy stuff that he laid on pretty thick".
All killing is a sin. When Joe kills your brother, it's a sin and it's a sin when you kill Joe in retaliation. It's a sin when Protestant Northern Irish kill Catholics and a sin when Catholic Northern Irish kill Protestants. It's a sin when countries kill in war; killing done by a State doesn't automatically make killing alright and blessed by God.
And: Just because you think it's OK to kill a certain category of person and I don't think it's OK to kill that category of person, that doesn't mean that I hate you, and it doesn't mean that I think it's OK to kill people like you. All killing is wrong. Simples.