Because we have the judicial system we have, appointed judges have had a good track record of protecting the minority viewpoint. Unfortunately, while that's had some positive results in civil rights, it has often meant the minority view of the rich and extra-enfranchised.
We Californians like our direct democracy but we're surprisingly cautious about it. Though bad laws get through all the time (as it is with democracy), the default vote is "no" on all things. This is how Schwarzenegger twice took a shellacking when he tried to maneuver his legislative agenda around the Senate/Assembly by calling for special elections. We don't like games.