There's all the difference in the world: one group is alive and the other isn't. There can be no anguish, satisfaction or any other trace of emotion in destroying droids... Lucas effectively sanitized a huge aspect of war in order to avoid having the Jedi cut up living beings with their sabers.
Which would have given Star Wars a more adult rating, thus limiting the turn out of children which has always been a main staple of the Star Wars audience.
As far as emotion over destroying droids, how many of us that watched Star Wars when we were young were emotionally upset at seeing R2 & 3PO shot or destroyed?
I know I myself was satisfied at seeing someone destroy a Droideka.
Hey, it's possible to employ robots as warriors and make it interesting or suspenseful. I think
Hardware did a good job of that, as did
Judge Dredd.
The problem with the prequels is that the droids are pathetically inefficient, Keystone-cop forces, that never once remotely create a sense of jeopardy for
anyone. In the OT, stormtroopers occasionally
win. The droids are just a joke.
The stormtroopers in
A New Hope wipe out Leia's crew, they wipe out the Jawas, they kill Luke's aunt and uncle, they destroy the entire rebel attack force except for a couple of ships. They somehow do this without getting an R rating. The droids run around, say "Roger roger" and bump into each other before getting destroyed en masse.