I think the idea of "the good" was probably a tool for manipulating people from the very beginning.
Finding circumstantial evidence for this in the paper Don linked to earlier.
Quote
In Homer’s epics, a unique value system is founded on convictions about the superiority of people of good birth, whose task was basically to take part in warSolon, in his poetic works, indicates the necessity of subordinating the value system to political activity
Theorizing about Good began with the emergence of Pythagorean philosophy....There are three aspects of this first philosophy school that can be discussed.7 First of all, it worked as a religious-cult association, which had its origins in Orphic religion. Secondly, it was a school with a political character
Also, these Sophists sound interesting. They have the right enemies. And in a striking similarity to Epicurus, their name has become synonymous with false reasoning.
Quote
The philosophical idea that refused to grant any ontological status to the good is taken up and developed in new directions by the sophists......as in the case of other presocratic philosophers, we have only fragments and other pieces of evidence to rely on, and many of them are preserved in the works of Plato, a violent opponent of the sophists [emphasis mine].
The enemies of the sophistic movement have accused the sophists of corrupting the minds and souls of Greeks (especially young men). According to them, the corruption was to consist in teaching that there is no absolute good or goods.
The reduction of the good to the purely subjectivistic area was made by the members of the so-called Sophistic Movement. Things for them are neutral, and the good appears as the effect of human activity. It is not, however, something objective, because it depends on the judgment of the individual person or a group of people.