I just finished my first game under beginner mode and I thought it was really lame when pirates entered the galaxy about 10 years into the game. They were extremely powerful and destroyed all my ships & starbases, but they wouldn't attack my planets? Eventually they put the Drengin out of commission and I formed an alliance with the other 2 races left standing and won easily.
Why does the game throw put such impossible enemies at you, the pirates' fleets had attack around 80 while my fleets were at around 20. It really didn't make any sense that I had won, I'm sure there was nothing I could do because whenever I built a ship they would kill it.