This also reminds me of something that Ridley Scott said years ago. He was explaining his thoughts on the Space Jockeys (as they were then) and why the one in
Alien was carrying the eggs, and said "They're not from Mars so they're not gods of war". So it was as if any alien race that came from Mars would have to be warlike because of how we named the planet
.
It sounds very naïve but I think it's more to do with Scott coming with a perspective of early science fiction where aliens were couched in the familiar. Obviously
The War of the Worlds gave us that link with bellicose aliens and Mars and that continued on with
Flash Gordon,
Invaders from Mars and in more recent times with the Ice Warriors in
Doctor Who – there may be more examples still but I can't recall them.
Actually, Scott's thoughts in the early stages of
Legend about Jack were similarly quaint – I mean that in a nice way, a creative way. Initially he was thinking that being of the forest, Jack could be green.