Besides Mobsters being quoted as saying that Joe Kennedy was the biggest crook that they ever meant, the JFK Administration attacks on organized crime and criminal activities of union bosses, perhaps IF Oswald did NOT shoot JFK than the mob did, and the mob also shot RFK as retribution for these attacks on their organizations during the JFK admin. Maybe the Teddy incident had something to do with another attempt or perhaps a Serious warning not to interfere with them any longer (something along the lines of Mario Puzzo’s horse head in the bed).
All conjecture on my part. I honestly believe that Oswald did in fact assassinate JFK and Sirhan Sirhan acting independently assassinated RFK. But if you want a conspiracy theory mine is that JFK sought to knock out the competition from the Kennedy family’s crime activities.