Imagine someone old and creepy like Biden but extremely smart and built like a Texan shithouse, who liked to press up against people to pressure them for support, and played with his dick in front of friendly reporters who annoyed him. LBJ gave us the civil rights act under the premise that he'd have niggers voting D for the next two centuries. He also gave us a little thing called the Vietnam War which was just as fake and gay as operation iraqi freedom but with a higher death toll, higher cost and more.
He easily ranks among the most damaging presidents the United States has ever had, and he probably would never have been president if Kennedy hadn't been shot. Johnson's entire purpose for most of his life was to climb the Washington power ladder and he absolutely hated JFK because he just waltzed into the presidency instead based on his name, wealth and looks.
I don't doubt the CIA could be involved either but LBJ was like a more imposing male Hillary Clinton so it's not like they're mutually exclusive theories.