The Jedi are pricks. How is eliminating the Sith upholding the balance of the universe? Aren't both the light and dark sides necessary for balance to exist?
Anakin only turned to the dark side because the Jedi council treated him like shit, lied to him, broke their own rules multiple times, and were massive hypocrites all to prevent a self-fulfilling prophecy of Anakin from turning to the dark side from taking place. The Jedi are themselves responsible for every single problem of the Star Wars movies through their assaholism and douchebaggery.