Who else was he an agent for, by that theory? Read what Ion Mihai Pacepa said. Oswald was a diehard Marxist. He had inside information which, when supplied to the Soviets, allowed them to shoot down the U-2 piloted by Gary Powers. He nearly killed anti-Communist U.S. general Edwin Walker. Pacepa claims he was not acting under Soviet orders when he shot Kennedy, but who knows; maybe he was, but that would just be too explosive for them to admit. Certainly the KGB was very capable of spinning out the disinformation campaign which deflected attention toward the Mafia, the extreme right, etc.
I don’t think Oswald ‘was’ a U.S. spy.
I wonder if the U.S. intelligence agencies believed he was a double working for them, and they were being duped.
That is why I compared it to the situation with Waco and OKC.
The FBI thought they had a double agent, but he apparently had other thoughts.