The game isn't trying to provide a pre-built universe, it's trying to give players the power to explore and create. The best way to think of it is that the galaxy is a framework to help you create. If someone is from Forge, you get a chance to think about how their clothing, technology, health, mannerisms, culture, etc might reflect their upbringing on an industrial factory world with all the pollution that entails. Then, you can compare that to someone from Harvest or Windsong and because the game encourages you to think about these things rather than just giving you 13 generic species, it'll hopefully let you engage with it on a deeper level.