Blizzard was obviously "parodying" the Colonial Marines from Aliens. If you click on them enough, they'll even quote Aliens (as will the Dropship). A little bit of comedy makes almost everything legal (in the US).
Early Blizzard employees have given at least one interview where they said that Warcraft and Starcraft were inspired by their love of the Warhammer and Warhammer 40k universes.
