Two hundred years ago everything changed; we made first contact. And it was a complete disaster.
Of course we didn't understand them and those in charge were convinced they were attempting to invade. So they pushed the button and in doing so turned was had been a peaceful attempt at trade into a full-on invasion.
As is typical during most wars, our technology advanced at a rapid pace, even more so once we captured one of their ships and managed to reverse engineer the tech on-board.
Now we travel the stars, defending our planet instead of exploring the wondes of the Universe. It's been a hard fight, they with advanced tech, us with tenacity and stuborness.
Now, after so many years, both sides are suffering from the prolonged conflict, but neither want to admit defeat. So we fight, and we die.
Something has to change.