The chief executive of a group that produced a wildly popular video about African warlord Joseph Kony answered critics Monday, defending its tactics and spending practices. "I understand why a lot of people are wondering, 'Is this just some slick, kind of fly-by-night, slacktivist thing?' when actually it's not at all," said Ben Keesey of Invisible Children. "It's connected to a really deep, thoughtful, very intentional and strategic campaign." In an online video that runs more than eight minutes, Keesey acknowledges the sting of criticism since Invisible Children released the video "Kony 2012" last week, becoming an Internet sensation with...