With Django Unchained and Zero Dark Thirty in theaters at the same time, it is revealing to compare them. Both are manipulative entertainments profiting from a taste for violence, but they get away with it — that is, they are actually honored — in different ways.
Bigelow wallows in the violence of imperial war exploits with just enough ambivalence that discerning viewers can comfort themselves that her movies raise important questions about that violence. What is never questioned, however, is its justification. In other words, the end justifies the means, though maybe not any means.
Tarantino has also landed on the formula that the end justifies the means: any means as long as the end is unquestionably justified. Thus, in the context of the Nazi holocaust or American slavery, few people would begrudge the vengeful violence that Tarantino obsessively presents.
In short, Tarantino avoids questioning the means, and Bigelow avoids questioning of the end. Thus each of them allows an unquestioned indulgence in violence as entertainment. There is no reason to consider their films as anything more serious. Bigelow and Tarantino are poseurs.