I think the notion of justice is very relative.
So if my society decides that murdering you is just, you'd accept that, in order to avoid interfering with my society? Are there no bounds on the freedom of societies to define justice? And, if not, what basis is there for any of your criticisms of American/Western/whatever ideas about justice?
More crimes are conducted by democracies in the name of justice today than are ever condoned by the forgiveness of some criminals by those most affected by their crimes.
Those most affected by said crimes are
dead. They cannot forgive anyone, and presumably would not wish to if they could.
Allowing the perpetrators to speak for the victims is possibly the most blatant perversion of justice I can imagine.
If a society believes that a justice system works for them, perhaps interference is not helpful.
I have yet to hear any affirmation from the societies in question that they are satisfied with said practices or how they are handled by their respective justice systems. On the contrary, I get the distinct impression that they are highly dissatisfied with them. You don't speak for them, so your unsupported assertions have no weight.
Not that it would matter: since the murdered girls and women (and the millions of others that are intimidated into silence by the acceptance of the practice) have no voice in the society when it comes to these matters, it follows that any societal affirmation of the justice system would be invalid in the first place.
Not that any of this is relevant to someone coming to the United States and beheading his wife in the name of honor. Nobody is suggesting overthrowing Pakistan and changing their criminal code. We're talking about someone who came to the US from another society, presenting himself and his company as the face of American Muslims, and who went on to (publicly, brazenly) violate one of the most fundamental moral precepts of our society (and essentially every other society as well).
The Islamic Society of North America has the decency and backbone to stand up against this murder, abuse and sexism. So it seems to me that all of the societies in question here are in agreement in condemning the crime and wanting to see the perpetrator tried in the existing American justice system. This is not an instance of the West imposing its own social norms on some foreign culture, but rather refusing to accept the importation of certain barbaric practices from foreign cultures.
Your post-colonialist rhetoric is highly misplaced here, not least because it has you arguing that brutal oppression of women is indeed an acceptable, legitimate part of certain Muslim societies, and that this is not to be criticized. This not only reinforces perceptions of said societies as backwards and barbaric, but undermines your moral authority by showing you as an apologist for oppression. I thought you always support the underdog? Are women that can be publicly, brutally murdered, without any consequences, somehow not sufficiently marginalized and oppressed for you?