Why is public awareness an important condition for democracy to function? Why is democracy often called the best form of government?
The basic idea of democracy is quite simple, but the details get quite complicated. The basic idea is just that the people vote to choose who will be in charge or what policies will be made. It contrasts with other forms of government such as dictatorship, where one person makes most of the decisions, and oligarchy, where a small group of powerful individuals make most of the decisions.
But in order for democracy to really work in practice, people have to have at least a basic idea of what it is they're voting for. If people had no idea who the candidates were or what they would do in office, voting would be meaningless, basically just random. This is why we need at least some minimal level of public awareness for democracy to function; people must know what they want, and which candidates are most likely to give them what they want. One of the most common arguments against democracy is that people, or some specific group of people, lack the necessary awareness to vote wisely, and should therefore be "protected" from their own bad decisions. The idea is not obviously nonsensical, but historically, following this argument has almost always led to oppression and persecution.
Indeed, it should really be no mystery why democracy is widely considered the best form of government. There are two quite fundamental and overwhelming reasons: One theoretical, the other empirical.
The theoretical reason is that if a society is supposed to act in the best interests of its population, the only way to do that is to have some mechanism for determining just what those interests are, and ensuring that the system of government is responsive to them. Voting provides just such a mechanism. While conceivably a dictator or oligarchy could have the best interests of the people at heart, there's nothing to guarantee that this will be so, because the process of selecting leaders and policies in those systems is in no way tied to the public interest. Whereas, in a democracy, the selection mechanism is directly linked to what the people want, or at least what they think they want.
The empirical reason is that democratic countries are just... better, by almost every conceivable measure. They are less likely to fight wars with one another. They have stronger economic growth and more stable economic prosperity. They almost never have famines. They almost never commit genocide. Their education level is higher. Their lifespans are longer. Their crime rates are lower. People are just richer, safer, healthier, and all around happier in democracies.
There are those who think that democracy is overrated, or at least that it's possible to become too democratic; but the empirical evidence really is quite strong that at least within the range of real-world countries (even Switzerland is not totally democratic about everything), more democracy seems to be almost always a good thing.