Peele saves his final trick for the last moments. It was always assumed that Red was tethered from birth, just as Adelaide had grown up free. But that's not actually the case. It's the child version of Red we see above ground with Adelaide's parents. When they met in the funhouse mirror maze as children, Red chained up her twin in the tunnels and swapped places, reaping the rewards of a life in the light. It's not Adelaide who we see watching the MTV promo in those first frames; it's Red. That's where her mission began.
It's a searing indictment of Hands Across America, which claimed that all Americans are just brothers and sisters wanting to help each other out. That wasn't the case then, and it certainly isn't now. Just think: As Hands Across America was failing to reach its goal, people around the country were dying of AIDS, a crisis the Reagan administration belittled. That same president popularized the racist notion of the "welfare queen," a nasty stereotype of black women that still haunts the political discourse, escalated the oppressive and still ongoing War on Drugs that has nearly exclusively targeted people of color, and operated under "trickle-down economics," which hoards wealth for the already wealthy. It's in this nation's nature to leave some behind, and in Us, those people are represented as the tethered. When Adelaide asks Red who they are, she responds: "We're Americans."
Throughout Us, Peele homes in on class divides, big and small. Even before they are attacked, the Wilsons are in competition with their friends Kitty and Josh Tyler (Elisabeth Moss and Tim Heidecker). Adelaide's husband Gabe (Winston Duke) buys an older fishing boat to impress Josh, who has a bigger, fancier tugboat. Kitty, a two-time actress in commercials who swears she could have made it big if not for having children, gabs at a resistant Adelaide about facelifts and her constant quest to stay young while drinking rosé on the beach. The Wilsons have means, but not the means the Tylers have. But to the tethered, they are living extremely well.
That last revelation about Adelaide's true nature is another layer of hypocrisy Peele adds to the pile. As a child, this woman climbed her way out of hell and refused to look back. Even now she relishes in her personal triumph over the ones she abandoned, locking eyes with her son and smiling just a bit. Here, no one is innocent. The desire to thrive in America makes monsters of us all.