Kubrick's war films: Paths Of Glory, Barry Lyndon, Dr. Strangelove, and Full Metal Jacket all carry the same basic message: that wars are futile.
In POG the French and Germans fight and fight to gain or lose a few inches of territory in grueling trench warfare and thousands of men die in an hour in a botched attack).
In BL, Barry Lyndon wanders through Europe serving in the British army, then deserting and being captured by the German army, which forces him into service until he can desert them in turn, all the while taking part in battles he doesn't even understand the purpose of.
In DS, Lionel Mandrake is the lone voice of reason, trying to figure out the point of a military strategy dreamed up by apparently mentally unbalanced generals that he believes will inevitably result in the destruction of both sides.
In FMJ, Private Joker is an ambivalent participant in combat during a war whose aims he does not see as particularly meaningful to him or to the Vietnamese.
And of course there is the comic ‘pettiness’ of the Cold War rivarlries in ‘2001’. I’ve always thought the war films tie in to the general Kubrick theme of a highly taut ‘system’ or plan for group coodination spinning out of control (race track robberies, infallible computers, impregnable hotels, perfect marriages (Eyes Wide Shut)...).
Have you ever heard about the story behind Gus Hasford?
http://en.wikipedia.org/wiki/Gustav_Hasford
He was the Vietnam Vet who wrote ‘The Short Timers’ which FMJ was based on. He was supposedly somewhat disturbed and had problems getting along with Kubrick and dissociated himself from the production early on.
And in Spartacus, the rebels are killed by the Romans at the end.
Yes, those are the plots of the movies, much like John Wayne is killed at the end of The Sands of Iwo Jima, or like how Tom Hanks is killed at the end of Saving Private Ryan.
Kubrick was fairly adept at not making political comments about his movies or what he wanted to convey. He just told good stories.
I don’t think that “war is futile” is what most people take away from his films.