Polygon has an interview up with Dave Theurer, the designer of Missile Command.
Theurer made it clear when agreeing to the concept that Missile Command would only be a defensive game, never offensive. "Realizing that the bombs would kill all of the people in the targeted city, I did not want to put the player in the position of being a genocidal maniac," says Theurer.
He refused to do anything that had players firing missiles at other countries, especially the USSR, which was a hot issue at the time, landing right in the midst of the Cold War. To him, this made it moral. You're defending your country against attack, and "defending against such an attack would be a noble effort." The idea of defense was one that players could take pride in, while slowly realizing what the game was forcing them to do: choose between the death of the few or survival of the many.
It’s interesting to consider this. I wasn’t around for the Cold War, but one does wonder if the people doing modern war games—Call of Duty, et al—have similar thoughts, when considering near-future war and the associated grimness that presents.