I think the originals are excellent films with an overall positive message, but looking back there are two or three details that stand out to me.

Everyone in the Empire is white and evil. The good guy rebels had the non-whites and aliens on their side. It’s the same diversity message, just low-key.

The main female character is of course a feminist who “don’t need no man”. She was the low-key precursor to Daisy Ridley’s Rey.

The white males on the good guy’s side were flawed characters who had to overcome their faults to become great. (Luke the delusional dreamer, Han the selfish scoundrel)

Leia didn’t have any faults. (unless you count arrogance, but that’s what a “strong woman” is) Lando didn’t have any faults either. He only betrayed them at the start because he had a gun to his head. He was otherwise an exemplary figure.

They came out around the 70’s right? That was the beginning of the end basically, with the Civil Rights and Women’s Liberation movements. (And right after the 1965 Immigration Act)

On the other hand, I also see Christian themes, especially in Return of the Jedi.