This game spent 3 years in early access.
The main reason as to why the game doesn't have lethal weaponry is because the game was first released around the time of the Sandy Hook shooting. Charlie Cleveland, the game's director, while not a believer of violent video games being a catalyst of violent crime, decided to make Subnautica a game without guns (not including the stasis rifle, which acts similar to a gun but doesn't cause violence).
The original plan for the game was for the Aurora to be a terraforming vessel. In later versions, the player is part of a mining crew aboard the "Aurora Mining Vessel." This was later changed again to just a "long-distance vessel" assembled to build a phase gate.
Many of the people who've gotten into, or at least heard of, Subnautica have done so because of JackSepticEye or Markiplier. In one of Jack's videos, he says that he met the Subnautica devs and they actually credit him for saving the game by rescuing them from the brink of bankruptcy. Presumably this is why Jack's eyeball mascot is in the game as a special item. Markiplier also has a easter egg in the game. Mark has shown his support and has already made 76 episodes on the game.