It is the essence of democracy that people should be able to decide the moral rules that govern the nature of a community. If people don't have that power, then they are living under an autocracy.
True, this majority rule is not unlimited. It is limited by what the government has the power to do. Consequently the majority cannot, in general, vote to seize the homes and accumulated savings of rich people. Leaving aside exceptional cases, government cannot mandate how parents how should raise their children. These kinds of power lie outside the scope of government in a free society.
Majority rule is also circumscribed by individual rights. But these are the rights clearly specified in the Constitution. A majority of citizens cannot prevent an individual from voting because voting is a basic right, as is the right to freedom of speech and freedom of religion, and so on. The state is constitutionally prohibited from undermining these enumerated rights.
Now the high court of California has made gay marriage into a right that is immune from restriction by the majority of citizens in the state. We already know what California citizens think about gay marriage: they oppose it. A referendum outlawing gay marriage was passed with the support of the state's voters. More than 60 percent of voters cast their ballots against gay marriage.
How, then, can a court invalidate the referendum and over-rule the will of the people? Basically through a kind of legal fraud. The court has to pretend that there is a right to gay marriage even though it is nowhere evident in the state constitution. Read the constitution, hold it up to the light, squeeze lemon juice on it--you won't see a right to gay marriage in there. It is simply not an enumerated right, nor is it a right that can be clearly derived from other enumerated rights.
In issuing its ruling the California court appealed to the equal protection clause of the Fourteenth Amendment. The basic logic is that gays have a right to be treated like everyone else. But just like everyone else, gays do have the right to marry. They have the right to marry adult members of the opposite sex! What gay activists want is something else: the right to marry members of the same sex. This is not a right currently enjoyed by anyone. What these gay activists seek is not equal treatment but rather to change the definition of marriage.