You seem to be new here...
Years ago, the human race came together for the first time in history to defend against an invading force of aliens. Since then they have remained as one, in the hopes that no other aliens would try to invade their territory. One of the side effects of humanity coming together, is that they are now a militaristic society with a focus on a "Only the toughest should survive" mentality.
Luckily you're born into a world where cloning is as common as being vaporized by plasma.