Right way to express disapproval of a culture, tradtion, religion, etc:
Orally or in writing in an appropriate venue, inviting discussion and criticism, and using the interplay as means to refine or revise your argument.
Wrong way:
Murder practitioners of the offending creed. Human beings can sink to some very low depths in the name of glorified tribalism, and the deliberate murder of a pregnant woman and her husband simply because you don’t like the implications of her clothing is a few fathoms down on that scale. (Not so bad as, for instance, killing and/or displacing millions through a misguided invasion of an entire country, just to pick a theoretical example, but a horrible crime nonetheless.)
Muslims are justified in their outrage, in this case, both over the crime itself and the tepid media response to it. They are correct in saying that had a Muslim attacked a member of some other ethnic or religious group, news tickers on every TV news network would have reported the killing over and over at the bottom of the screen during the 24 hour Michael Jackson coverage.
Based on recent history, though, it should be pointed out to the more radical among the Muslim community: justifiable outrage is not an excuse to riot in the streets. Do that and you’re just lending credence to the lunatic fringe that might be inclined to support this man’s actions. Do that and you continue to perpetuate a justifiable-outrage circle-jerk that will keep on begetting violence and distrust on both sides long after you’ve gone off to meet your version of the invisible sky wizard. (Besides, it’s not as if the guy drew a picture of Mohammed or something…)
I should also point out that this man’s vile actions and the seeming lack of western interest in said actions are in no way a repudiation or validation of your repressive, misogynistic traditions. Your head scarves and burqas are the symptoms of a belief system in which women are little more than property, subject to beatings and execution if they, willingly or not, step outside the narrow, puritanical set of behaviors you have defined for them.