These people seem to think that history began in 1965. Did they ever hear of Birth of a Nation or Gone With the Wind?
I would argue that two of the most influential films of all time are Sergei Eisenstein's Borenosets Potemkin (Armored Cruiser Potemkin) [1925], which is said to have inspired revolutions, including the one in Cuba, and Leni Riefenstahl's Truimph des Willens (Triumph of the Will) [1936], whose influence can be seen in films ranging from The Sound of Music to Star Wars.
While A Clockwork Orange is a good period piece from an era when socialism and behavior modification were in vogue, I would hardly call it influential.
I think you are correct about the influence of those two films, much as the world may resent the political sympathies of the two directors.
I think Star Wars changed the culture. It changed what we expected from movies, put classical music on the charts, emphasized the good vs. evil empire we were experiencing at the time.
Heck, remember Reagan's "star wars" project that is partially credited for ending the Cold War? And look at what it did for computer animation, which affects practically everything nowadays. It was a watershed film.
Star Wars is probably one of the most influential films ever made.