Randall Flagg's Las Vegas operates. It's always made sense that the demonic Flagg chose to build his post-plague version of society in the so-called city of sin. Las Vegas has a reputation for being a place where anything can happen, and where dreams and wild fantasies can come true. Whether that's true or not is up for debate, but thematically, it fits Flagg like a glove.
While it might seem obvious to an outsider that Flagg is evil, that's not how he presents himself to his followers. To them, Flagg is a savior, promising a safe, prosperous life following the devastation of Captain Trips. The thing is, he can indeed provide that, at least to an extent. That changes when someone makes the unfortunate decision to challenge his power or question his decisions, as Flagg's Las Vegas is definitely not a democracy, and his word is law.
That might sound like an obvious downgrade from the Boulder Free Zone's attempted democratic society, but history is full of people willing to trade freedom for security. In The Stand 2020, Flagg's people also get seemingly unlimited hedonism in their downtime, but that's a complete 180 from Stephen King's book.
How The Stand 2020 Drastically Reinvents Randall Flagg's Las Vegas
Episode five of The Stand 2020 spends much of its running time in Randall Flagg's Las Vegas, focusing on the activities of Boulder Free Zone's spy Dayna Jurgens. Through Dayna's eyes, we see that Flagg's "New Vegas" is a den of debauchery, with the residents free to indulge in any base pleasure they see fit, provided they also do the jobs assigned to them. Characters do drugs, get drunk, have public group sex, engage in no holds barred fight pits for fun, and are generally uninhibited by the former constraints of living in normal society.
To those unfamiliar with Stephen King's book, that might seem fitting for the side of evil. But the Flagg in the book allowed no such behavior. Flagg ruled with an iron fist, banning vices like intoxicants and prostitution, partly because he wanted his people clear-headed and fully able to do the tasks he needed them to do. In fact, those who disobeyed Flagg sometimes found themselves publicly crucified as an example. While The Stand 2020's producers have said they changed that to try and make siding with Flagg look more appealing, and for the right kind of person, it certainly would, it's definitely a fundamental change to how Randall Flagg thinks and controls his society.