I'm to the point I really just don't trust the media to accurately report stories like this. Seems like there's always a "rest of the story" that we don't hear about until later.
I agree, that's why I looked into it more and found the rest, including an elaboration on why he was exonerated of premeditated murder. But, without a doubt, he definitely hung that slogan over their bodies after killing them. I don't see how that's excusable. He would've been prosecuted for that, but after the first charges were dropped, the only person who could bring up anymore said he should be punished in another way.
And if we do take things like this in the military more seriously than we do elsewhere, it's because we entrust the military with hardware capable of killing large numbers of people (up to and including thermonuclear warheads). So yes, we are compelled to take misconduct there more seriously than in the corporate or individual level.
I don't know if it needs to be taken more seriously necessarily (you could say I'm neutral on the subject), but what bothers me is the attitude that a lot of people in the media and the populace at large have, that the military is always blameless and full of perfect individuals. I do think people in the military are more disciplined, patriotic, and capable than the populace at large. I do think that they do an amazing job of dealing with the awesome responsibility and power that we place in their hands. That does not mean that every member of the military follows these trends.