Zeus, the ruler of the gods, retained his power by using his intelligence along with superior force. Unlike his father (whom he deposed), he did not keep all the power for himself but granted rights and privileges to other gods. He was not an autocratic ruler but listened to, and was often persuaded by, the other gods.
Openness to discussion and inquiry is a distinguishing feature of Greek theology. It suggests that collective decisions often lead to a better outcome. Respect for a diversity of viewpoints informs the cooperative system of government the Athenians called democracy.
While the Greek gods do occasionally discuss, and collective decisions do lead to a better outcome, it's not really true that openness to discussion and inquiry is a distinguishing feature of Greek theology: one could just as easily say that quarrelsomeness is, since the gods are constantly bickering and taking vengeance on each other (usually indirectly, through the lives of mortals). And the Greeks themselves were often more cynical about the gods; Euripides, for instance, suggests in the Hippolytus that the principle of harmony among the gods is not discussion -- neither Aphrodite nor Artemis consult with other gods -- but simply that "no god can go against the fixed purpose of another". And mortals suffer for it, as Hippolytus does, as Artemis promises that Aphrodite's favorite will suffer for it when Artemis gets Aphrodite back. In fact, there is no 'distinguishing feature of Greek theology', unless by 'Greek theology' you mean 'Neoplatonism in the Roman Imperial period'; the rest is discordant tradition and differing views.
In any case, Lefkowitz's argument isn't new; Hume argues the same thing in The Natural History of Religion. But Hume argues that the intolerance of monotheism is connected with reason: monotheism's intolerance is linked with the fact that it grows out of reason, whereas polytheism grows out of sentiment. The more philosophical the Greek pagans became, the more focused on reason, the more their views tended to approximate monotheistic ones. He also notes that the same tolerance that allows polytheism to accommodate other polytheisms allows it to justify any practice or opinion without falling into inconsistency; which is not such an advantage when the practice or opinion is a bad one. And thus he argues that both polytheism and monotheism are bad for morals, not because they are the origin of these moral flaws, but because they both in their own ways aggravate some of these flaws through their practices, although in moral doctrine they offer ideals worthy of respect. As Hume notes:
Hear the verbal protestations of all men: Nothing so certain as their religious tenets. Examine their lives: You will scarcely think that they repose the smallest confidence in them.
It's worth pointing out, incidentally, that both Lefkowitz and Hume, in lauding the tolerance of polytheism, overlook the fact that polytheism has always had difficulty being tolerant of monotheism, precisely because monotheism doesn't play the polytheistic game; and there have been plenty of cases of polytheistic intolerance of monotheism. Likewise, they overlook the fact that Jews, Christians, Muslims, Sikhs, &c., are not intolerant of each other's monotheism; occasions for intolerance lie elsewhere.
