There is something we notice about the cities of the Ionian coast in modern western Turkey, for instance, in the century or so after the invention of money. This is the 7th century B.C., when trade flourished through Lydia and Ionia with goods transferred between the mainland and the ships of the Greeks and Phoenicians, who carried the goods of Mesopotamia throughout the Mediterranean. The political chambers of these cities are designed for what we call 'democracy,' but what is more properly called the origins of argument. These are structures that are built like pits, with seats that politicians sat upon and that faced inwards. The politics of earlier cultures like Egypt, Mycenae and Sumeria are very much linear, where chambers were built for kings to give orders to underlings, who carried them forward. Ionia, however, is the beginning of fighting. These are the first societies where discontent, disagreement or even hatred were normal parts of the culture in which the inhabitants lived.
We are so used to this now, but there was a time when disagreement within a given clan or tribe, even within a kingdom, was treated with incomprehensible intolerance. Citizens were not merely tax slaves, they were mind slaves as well, and a single note of discord was met with death.
Of course, this disagreement tolerance in the cities of Ionia was for the privileged class. The bottom feeders, the slaves, the peasants and so on were still routinely executed for having a thought in their heads that managed to escape into vocalization. Only the wealthy were entitled to an alternate opinion, only the wealthy could speak that opinion aloud . . . and when they did, it was praised and considered with the highest esteem.
This hasn't really changed, though some like to think it has. The principle difference is that the bottom-feeders, like us, aren't executed for speaking, but everything we have to say to each other continues to have little or no relevance to the elite. There are chambers for them to argue within, and the arguments that they make are praiseworthy, but the chambers that we argue in are meaningless and dismissed.
We hope, of course, that one day we will be allowed to disagree in those chambers, but we know that's improbable. We had our opportunity when we decided not to enter politics or business, or to keep on with our educations, striving for tenure at some relevant university. So it goes.
What, pray tell, does any of this have to do with D&D?
Beyond the reality that this has a lot to do with everything, nothing special I suppose. Except that I think that disagreement at the table need not be viewed as a bad thing. Players having it out about something they've come to a head over does not necessarily mean that the party has decided to split. It could, in fact, through resolution, if both sides are just left alone to argue, make the party stronger.
Sometimes my role as a DM is to shut the hell up. Sometimes, that's the best thing for everyone. We founded this flawed, difficult culture upon arguments and shouting, in pits especially designed for those arguments, 2,700 years ago. We ought to, by now, recognize the benefit of letting the participants in the pit fight it out.