Being a jerk leader is an effective way to get the most out of your largely lazy and unmotivated underlings. Steve Jobs, Michael Eisner, and Larry Ellison did not become successful bosses by being nice guys. They were all infamous for their temper tantrums and general nasty treatment of their underlings. Their abusive behavior was an asset that helped them rise to the top.
Research shows that mean behavior at work improves people's perception of your competence. They may not like you, but they'll think you're smarter and better than them. That's the way you solidify your position of authority and get the grunts working harder.