system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it that we always depict human's style in Sci-Fi as utilitarian, and aliens as organic/stylized?

From Alien, Avatar, Independence Day, StarCraft, Warhammer 40k, Star Wars, Halo, Star Trek, and recently Ender's Game. There are countless examples where we seem to think that aliens are willing to give up function for form, or have so mastered function that they can accommodate form. Humans are almost always limited to relatively unexciting extensions of modern day military technology. 

The Terran, in StarCraft, for example, are stuck with squared or beveled edges, boxy, sturdy designs. The Protoss pay tribute to an almost Egyptian style, with a very regal and ancient feeling, with a lot of curved edges and distinguished style.

In Star Wars, even though we're not strictly dealing with "humans," the empire still sticks with fairly mechanical and rigid looking structures. The Millenium Falcon fits the same bill. Compare that to the Gungans, or the Mon Calamari, who have flowing and organic designs.

What I find especially interesting about all of this, is that these are all works of fiction that are designed BY HUMANS. We design the Protoss, and the Formics, the Romulans, but we don't see any of these creations as a reflection of ourselves, or as something that humanity would ever bother facilitating.
gpt
This isn't necessarily the best question for this sub. We're all about trying to explain science fiction in the context of the universe the work is set in. We don't necessarily care about why certain artists choose certain aesthetic designs. 

That being said *ahem*

So writers are (almost) entirely human, and science fiction is for (again, mostly) human audiences. So there needs to be clear visual indication that something is of "Human" origin, as opposed to alien origin. And big, boxy, non-shiny spaceships have enough precedent that they're basically the norm for designing a human ship. 

It's also important that shiny curvy spaceships being piloted by aliens is way older than humans driving  boxy spaceships. If you're a science fiction writer who is trying to make a spaceship for humans, then you need to somehow make them distinct from alien spaceships. So they just made the ships as "unalien" as possible, which happens to be the more "function over form" aesthetic that is in stark contrast to the shiny, curvy aesthetic that Alien ships possess.