Wired gives Star Wars a good drubbing, focusing on the ending:
There are somewhere between 20 and 30 one-man fighters in the assault, right? And of all of those guys, only Luke, Wedge and some guy in a Y-wing make it back (and Han and Chewie, of course, but they weren’t part of the original team). So that means that in this fight, despite its amazing success, the rebels lost somewhere between 17 and 27 of their very best, bravest pilots. Yet all they can do is cheer as Luke descends the ladder of his X-wing. Luke cheers, too, hugs Leia, and is absolutely ecstatic … until he realizes that R2-D2 got badly damaged in the fight, at which point he is nearly distraught. Losing fellow human beings, including a good friend of his, that doesn’t matter; possibly losing a cute but replaceable machine, now that’s sad. —GeekDad
Got to agree with Mike’s comment. In SW the robots transcend robotness. The robots are stand-in’s for the downstairs folks who serve and hover almost invisibly in the vicinity of Luke and Leia upstairs folks. It’s only right, in the context of the story, for Luke to feel compassion for his injured, but still living, companion who helped save his keister. It would have been wrong to disregard R2D2, because in the movie R2D2 really was more than a robot. If R2D2 was simply a machine without human character then no one would have worried about him any more than an damaged spaceship.
Not that I would put SW up as an example of wartime mentality, but the sequence where the X-Wings are picked off one by one is quite long; there are endless cuts back to the grim faces back at the rebel base, the other terrified pilots still alive, and Luke growing increasingly shaky with each sudden death. It certainly mattered.
And who wouldn’t want to cheer the few that returned from an basically impossible mission? The time to mourn is later, if at all – X-Wing pilots seem to have been as ephemeral as WWI biplane jockeys – and a battle where your side loses 17-27 men and the other side loses the entire staff of a giant space station – at least in the thousands – is, well, a relatively painless victory.
Also, R2 is clearly sentient. So why does he matter LESS than any of the other combatants? I sense robot bias.