Re: political correctness in regards to aliens.
There's an easy solution. We stop fucking portraying ethnic groups of people as inherently evil. Kill the "faceless mook" trope.
Making them "orcs" or whatever isn't really better. To eliminate unfortunate implications you have to eliminate excuses to hate entire groups of people.
As others have said, killing that kills a good chunk of media. The long and short of it is that (escapism aside), if an author/dev/whatever goes through the effort of humanizing and filling in motivations for everyone the protagonists come into conflict with, even when they literally
are faceless mooks, the story breaks. Not because there's something inherently wrong with humanizing the "enemies" of a particular conflict, but because doing so in a way that's even remotely effective creates massive amounts of what is essentially filler content, unnecessarily lengthening the work substantially, as well as making it unfocused and shaky (because so much time is spent on all of the secondary and bit characters that the main cast--on all sides--have less screen time, and thus less opportunity to hook readers/players/whatever on
their personalities and motivations.
Be honest, when you come down to it, it defeats the point to have a story that is about every single character that appears in it. I'm totally on board with the "lets' not encourage blind hatred of group X", but that doesn't equate to, "there can't be any groups of bit-character antagonists that have little or no characterization ever". If you write a battle scene in which every single soldier who's on-screen has their moment in the spotlight, for example, it's going to come off as (again) weak and unfocused. This is an incredibly basic element of characterization; characters tend to be increasingly dimensional in proportion to their importance to the story. A guard who appears for ten minutes and dies isn't worth more than a sentence or two of description, because
he exists to be there and die to help advance the plot. When a character is fighting against an authoritarian dictator, you don't stop to justify and explains the reasons that each of the state's soldiers has for serving loyally.
Leaving aside the practicality of it, it'd also be incredibly dull (not to mention removing the possibility of subverting the trope--that's entertaining precisely because it doesn't happen very often; it'd just be tired if it did).
Wait, why is this in the happy thread? o.0