Suspicions about JFK's assassination are actually some of the more "acceptable" conspiracy theories to believe in, in the US. However, I think Lemino's recent video has shown the online community that there really isn't much, if any, room to argue that it wasn't Oswald.
Doing it for a joke is fine. Actually thinking you're going to find something that the FBI missed and the thousands of other conspiracy nuts missed is pretty stupid and/or arrogant though.