[...] to condemn it for being dark is sort of antithetical to the film; especially when the logic of your condemnation is it's dark because it treats death cavalierly. Treating death with a lot of grim angst is the hallmark of serious minded fare like Ron Moore's BSG; shrugging it off by going off to save the day, blow up the Death Star or gamble on the Ovion planet is the staple of more frivolous, pulpy narratives.
I think that's conflating related criticisms, however. The content of the new Trek film borrows liberally from the genocide-chic phase of the last decade: two central planets blow up, one deliberately and with billions of people still on it*. It is, content-wise, dark. But it also adopts a mood (different from content) that goes for a light and breezy effect, which clashes--sickeningly, cloyingly--with the content. It's not a romp because it foregrounds murder on a planetary scale; at the same time, it isn't a serious piece because it barely pauses to attend to those issues. In trying to do both, it fails to be either, or anything really. Of course, I'm of the opinion that it never should have tried to be dark in the first place.