I think it is pretty clear why Lee Oswald assassinated John F. Kennedy. JFK was a Liberal Democrat, a cold warrior, a strong believer in liberal democracy and freedom for the individual. And by the time his life ended, he was in favor for freedom and equal rights for everyone. Which included non-Caucasian-Americans. Which put the Far-Right at odds with President Kennedy, who perhaps didn’t see him a strong threat before. And the Far-Left in America, which included Communists, that didn’t like President Kennedy’s tough cold war anti-communist stance against Russia and Russian allies.
Lee Oswald represented what Jack Kennedy hated, which was communism and a strong belief in a strong centralized authority. Where this huge centralized superstate would assume responsibility and authority for people’s lives and their well-being. Lee Oswald originally wanted the Russian communist system and thought that was the best way to go. He figured out he didn’t like Russian communism and left Russia around 1960 or so. And then decided that he thought the Cuban Castro form of communism, with a strong socialist system with generous welfare state benefits was the way to go.
Jack Kennedy and Lee Oswald represented what the other was against and at least in JFK’s case, hated. Again JFK Liberal Democrat, who hated communism and huge centralized authorities over the people. And wanted the power with the people to be able to make their own decisions. Lee Oswald, as a Communist was the complete opposite and even spoke up for Fidel Castro and the Cuban Communist State in America and passed out propaganda about the Castro Regime. Oswald saw JFK as a threat that had to go and had the means and opportunity to bring that about.
The only question I believe left with the JFK assassination, was their anyone else involved in the assassination along with Lee Oswald. Because JFK had plenty of enemies on the fringes in America. The Far-Right because of his civil rights stances and they believed he wasn’t tough enough on communism. And the Far-Left Communists in America who saw JFK as a threat to their system and ideology that they wanted to bring to the whole world. And organized crime, the Italian Mafia who saw the Kennedy Administration as a threat to their way of life.