You see the difference between "them" breaking into my home, and them coming to my country, is that the aforementioned scenario would require them to break the law. If they come to my country, while respecting the laws in my country, then they can't be defined as invaders (unless you don't care about what words mean).
We live in a globalised world now. We never did that before, so looking to history for examples is asinine.
So killing a 14 year old because they lean left on the political spectrum (or happen to be in proximity of people who do), can be defined as "the interest of his people"?
Also, what "people" are you talking about? I would dare to estimate that 99% of the norwegian population condemn and despises what he did. Do you define the "people" as the ones who share your worldview? Because that's luckily a very narrow part of any given population.
I notice you insist on being vague. Yes, you would PREFER less violent means. But do you object to the means Breivik used?
That is a simple question for most people, see if you can handle it.
So just to be clear, you don't approve of the ultra nationals in Italy killing that refugee? Do you think they should be punished for their actions then?