Wow, when would the rest of world do something
The USA is physically large and screwing with it will not happen early.
Basically, what I see happening is the United States falls into a dystopic "extremism of property ownership" where the right to property has become so extreme that many millions of people have died and only totalitarian control over the media, the complete lack of education in most of the people, and and a willingness to do whatever dark deed is required to keep the boss in charge keeps this running.
The United States also didn't become this way overnight. As grim as this scenario is, all that's really changed is that the Gilded Age Corporations are no longer run by morally conflicted men like Rockefeller and Carnegie--men who are at some level concerned about the human cost of their actions but their business comes first--but instead men like Pinochet, who lack that concern entirely.
Going from a nation that launches mercenary attacks against unions to going full Orwell on them doesn't strike me as all that radical a change. And as sad as that scenario sounds, I don't think the world intervenes for a long time. The USA enslaved millions of kidnapping victims and their descendants and while people cared about it, it didn't lead to war.
I think if the mantle fell to them, the Socialist Movement would take up the banner of human rights. In this ATL, it is clearly obvious that unmitigated Liberalism is horrifying for most people. A lot of people who probably would have been "Liberals" without that horror story become "Humanitarian Socialists" or "Christian Socialists". The rise of a more moderate Soviet Union analog might happen in Germany, and the Human Socialist / Christian Socialists coalition and oppose radical right-wing Liberals.
That's right, in this ATL, the Soviet Union really is the good guys. And they also win over the world. It probably takes until 2100 for the World to decide to force the United States to accept that individuals who do not register for full citizenship (ie 98% of the Population) deserve to have human rights acknowledged.
But this is really out of line to the United States. If you think about social issues in terms of profit and loss, why end child labor? Children are replaceable, indeed, thanks to birth defects, child replacement is common and legal--the United States doesn't need people who can't contribute, and infanticide because of economic loss is a positive good. Killing grandpa after he can't work anymore is good too. And if someone is willing to pay for sex, whatever emotional pain that causes, it's worth it.
What sort of culture does this create? A stoic one. Mankind survived the dark ages; times where whole families shacked in a hut and hard labor ruled lives. In a lot of ways, the United States would resemble that a great deal--but this is unfair to feudal lords, who generally wanted to help their peasants, as opposed to simply profiting from them. Mankind didn't necessarily have better choices in those times, but its not like the Americans in this scenario do either.
The question, though, ignores the partial avoidance of this scenario in OTL. I think in real life, the Trillionaires club would be legitimately scared and appalled at the plight of the average American. To a point, they can play the "Us and Them" game to avoid connections, but they can't entirely avoid the culture they've created. They'll see the people at the bottom, scared by disease, skinny from too little food, and stoic about having done very humiliating things to eat another day. People who no longer hold funerals because selling organs for money is financial necessity, or whose marriage can be defeated with a $20 bill. And eventually they decide that their culture sucks.
They can try to make a deal amongst themselves, but deals aren't law. Besides, the American People are basically unable to use the legal system, as they can't read. The endless liberty and unlimited right to use property without infringement, a product of a refusal to regulate and a consequence of a power elite that proceeded to completely win the culture war and then Orwelled everyone into loving it, quietly dies.
But it breaks the scenario. So that executive, despite his misgivings, decides that the Arbeiterbund's demands to abolish narcotics production, child sex tourism and tax evasion shelters are a fundamental infringement of the "Free Market" and will not happen. He then flies in his private jet to Washington DC, an oasis of clear skies in a nation of smog, to denounce "unjust demands" that are carefully remanufactured into absurd demands for abolishing shoes and belt buckles by the media.
It's just another day in America.