Or how about...all humans are flawed creatures who at times act in bad faith? Yes, this includes DMs, but we still have sheriffs and police in real life, right?
If the GM is guaranteed to occasionally act in bad faith, should we not prepare for that inevitability, rather than shrugging and saying, "What can we do?"
I think even among a group of well-intentioned people there has to be someone in the group whose responsibility it is to keep the peace and adjudicate decisions (here we call them "mods").
Who is the person with the responsibility to keep the peace and adjudicate decisions in a married couple? Who is the person with the responsibility to keep the peace and adjudicate decisions in a group of three friends who play a video game together on weekends? When going to a restaurant with (say) four friends to celebrate, whose responsibility is it to keep the peace and adjudicate decisions about who will eat what dish?
This assertion requires the idea that all relationships have a hierarchy. That's simply not correct. Some do not--and they address concerns in a different way.
Plenty of ways people interact with each other do not have a hierarchy, but they manage to survive and even thrive without an absolute authority dictating things for everyone else. We can, in fact, do something similar in TTRPGs--even if we
do allow one person more authority than others.
I know you didn't say otherwise so I don't mean to put words in your mouth, but I bet we both would agree that good people sometimes commit crimes and act in bad faith. They aren't a different breed of human.
Nor are GMs. Entrusting them with absolute authority, then, is simply inviting them to use it in the--as you yourself allege--completely inevitable event that they act in bad faith.
Because the DM's role is different, right? They effectively are the judge, jury and (figurative) executioner. Even in a creative endeavor like a sketch comedy show (let's say SNL), there's still going to be someone like Lorne Michaels who oversees things. Otherwise, it's chaos.
Again: there are myriad forms of human grouping where we don't have this, and yet life isn't constantly beset by "chaos". It's just not true that it's "otherwise chaos". People can and do work out their differences. And if they absolutely can't--if consensus is
truly completely impossible--then what makes you think a single person shouting everyone else down would somehow guarantee a fix anyway? If cohesion is already breaking down, what makes the fact that one person wears the pointy hat (crown, viking hat, whatever) magically able to get folks to calm down? You still have to have that foundation of
agreement to cooperate--which means your protection against "chaos" already required a foundation of
consensus anyway.
I'm not saying a group of people can't all come to consensus on their own sometimes, but I am saying that they won't come to consensus all the time without a DM.
I'm not saying that a single leader can't enforce decisions on a group sometimes, but I am saying that they won't be able to enforce decisions all the time without consensus first.
Two can play at this game--and it is the simple fact that government derives its power from the consent of the governed.