Reactions to the killing of Osama bin Laden were joyful, charged, polarizing — and, in at least one case, confusingly opportunistic. As you may recall, Rihanna sprung on the chance to tie the international incident, via Twitter, with the lyrics of her imminent new single, “Man Down,” which recounts a murder. Specifically: “Rumpupupum Rumpupupum Rumpupupuuum #ManDown” and “Obama Bama Bama sry I meant, oh Mama Mama Mama, I just shot a man down #brrrap.” Bold! And, also, ultimately disappointing: If you’re going to make the connection in public, would you at least have the common courtesy to then produce a video reimagining the brazen Seal 6 operation as being headed by RiRi and a trusty canine? Instead, we get a sultry, Jamaica-set clip that mostly consists of Rihanna bouncing around town ruffling kids’ heads while looking incredible — and, oh, right, an implied sexual assault and explicit murder. It’s all a bit out of character for Rihanna, who has almost always been sold as a fun-loving innocent (the dark ballads pegged to the Chris Brown incident are a notable exception). Unlike “S&M,” her previous, ill-fitting experiment in persona-tweaking, this one works, more or less, as a not-all-that-serious take on homicide-pop. Still disappointed this isn’t actually about Osama, aren’t you?