One of the few forms of defense that a young victim has against a school bully is humor, and so it’s ironic that the fatal flaw of the Owen Wilson bully comedy Drillbit Taylor is that the characters aren’t funny enough. Wilson plays the title character, a self-described “homeless U.S. Army deserter” who convinces a trio of nerdy high-school freshmen that he can provide protection from the upperclassman Neanderthal who has been tormenting them. Wilson mainly seems tired, while the three young stars offer little of the quirky wit that producer Judd Apatow is otherwise known for bringing out in unlikely performers.