Why Did Lee Harvey Oswald Assassinate JFK?

Although according to the US government's investigations, Oswald was held responsible for the assassination of John F. Kennedy, it is one of the most controversial topics in modern American history with seventy percent of Americans believing that it is a result of a conspiracy and not a single culprit case. It is even unclear if the conspiracy at all includes Oswald.  

Oswald had said that he was not guilty of this murder and that he was being taken advantage of. Having said the above, if there was a motive behind him killing Kennedy it was because of his involvement and his commitment to Marxism and communism. He was also a greatly dissatisfied individual who could not get along with the environment of people around him.

Long before his conviction and assassination, he had expressed his hatred for the society in American and he also protested against it. All of which led people to believe that he was motivated to kill the president.