I couldn’t disagree more. I don’t mind a little optimism, but the book ending is just pure fairytale, human brains just don’t work that way. You can’t just shut off psychotic and sociopathic thoughts at the blink of an eye just because you see an example of someone having fun without those thoughts.
I also prefer the only other major change that the movie made, to omit the part where he drugs the 10 year old girls. Kubrick may have only changed that because it would be too provocative but I still think it works better without it. I just don’t understand what about Alex’s screwed up mind would make him attracted to pre-pubescent kids, even though he’s clearly attracted to adult women at other points in the story. It just seems like a totally different kind of crazy than what Alex is.