For Greek philosophers like Plato and Socrates, there was nothing at all wrong with wine in and of itself. Quite the contrary, in fact, because wine was regarded as an important product of civilization which brings significant benefits. At the same time, though, they recognized in wine something with great potential for harm if used improperly.
Thus like so many other things, wine must be enjoyed in moderation — I can almost see Plat, Socrates, or Aristotle doing public service ads saying "please drink responsibly." One corollary of this principle is that those who are better able to control themselves are given greater freedom to indulge while those who are unable to control themselves get less freedom.
Implications of the Socratic paradigm for political thought were immediately visible in Plato’s political writings, the Republic and the Laws. We expect to see wine provided for in the Republic’s indulgent “City of Pigs,” but it is initially mentioned in the same breath as such ordinary items as bread, cloaks, and sandals (372a), as if it is not regarded as much of a luxury item in itself. However, we also see the expected passages condemning alcohol abuse (e.g., 389e), and we shall not be surprised if there are overtones of distaste when discussing the philoinos (“wine lover,” 475a), who welcomes any excuse to drink any kind of wine.
But it is the Laws that both regulates and institutionalizes the use of wine. The work is particularly keen to keep the potent liquid from those who are comparatively young, and to introduce greater quantities as life goes on, so that senior citizens who can best control its effects also receive the toughest challenges in their efforts to demonstrate their virtue. These older men are also seen to be in the most need of something to make them let their hair down a little, so that the state will provide occasions for them to drink!
Source: Fritz Allhoff, Wine & Philosophy: A Symposium on Thinking and Drinking
It must be admitted, though, that most Greek philosophers did not live independent of outside influences. In fact, many were dependent upon powerful political figures to some extent and all of those figures enjoyed their wine. Thus any direct attacks on wine and wine drinking could have alienated their patrons, resulting at best in a loss of income and prestige, but perhaps also the loss of one's life.
Greek philosophy thus could hardly have developed a strong encouragement of abstinence, so to what degree was the philosophy of moderation in wine drinking based on genuine beliefs and to what degree was it a rationalization of political needs? We'll never know, but this should be a cautionary tale for us to make us think more about what we read as well as about our own ideals.