What the movie means, how it affects people, how it reflects on the author, etc. are all out of his control, but the public doesn’t get to argue with him on what it actually IS.
Once the author dies, all bets are off because things must continue to change to remain accessible to others. Translations, data format changes, viewing methods, etc. all can require adaptations. Since we can no longer ask the author their opinion, we take the works as a whole. No future discussion of SW would be complete without taking time to reference the changes it underwent over time. If nothing else, it adds necessary context to understand the media.
IMO it’s also kind of a blessing. It gives us multiple angles to consider a work from when squeezing more meaning out of it 100 years down the road.