I don't really have anything new to add to the (growing) camp of left-wing criticisms of the completely ridiculous, politically insidious "Kony 2012" campaign. The people behind it are total douche-bags. The campaign itself uses moralism to cloak its imperialist "humanitarian intervention" politics. Here are a handful of pieces that I've found especially helpful on this question (feel free to suggest more in the comments):
Richard Seymour, whose excellent book The Liberal Defense of Murder is well worth reading to get a deeper understanding of "humanitarian intervention", has an excellent blog post here and a great article in ABC Australia here.
A comrade over at Needs Moar Class War has a detailed piece here that is well worth reading as well.
SW.org printed an article that nicely skewers the racist, colonial attitudes implicit in the "Kony 2012" campaign.
American Leftist has some thoughtful remarks and a link to a few interesting videos by Ugandans here.
Mahmood Mamdani, who's usually quite good on African politics (esp. on Sudan and Zimbabwe), has a short piece here on the controversy.