I've got no problem with Arcturus being a spot for a little marine R&R, nor that they were joking with Frost by calling him gay (whether he actually was or not - probably irrelevant). That all I pretty much took as a given anyway.
I've known some military guys, so I know the type; hell, me and my friends regularly do the same type of thing. You don't have to be in the army to point at a friend, go "ha ha ur gay" and giggle.
Plus, I was pretty much making Arcturus into a kind of "space Hong Kong" in an interstellar Vietnam-area for my game. There's lot of anti-colonial rebellion in that region of space, and Arcturus is the biggest colony in the area, so it's where the Colonial's take their furloughs.
Of course, that's all equivalent to fan fiction, as Meathead said, so it doesn't really many anything for the movie-verse as a whole. In general, however, with Space Jockey's about (somewhere, or maybe only in the past), Aliens (which may or may not be sentient, but are definitely dangerously intelligent), and maybe Predators (if you swing that way), I thought it would be interesting to play in the sandbox a little and let there be a few more non-major alien races scattered about.
It can kind of add to the "corporate exploitation" theme; the Company comes in to a habited planet, talks nice to the local aliens, and then pulls an interstellar American Indians on them.
Damn the man!
-Pax