This is nonsense. The US was a left-wing experiment. It was a repudiation of the way things were done in Europe. The fact that it didn't solve every single inequity in one blow is not an interesting observation.
It's fair game to criticize the US, but to misunderstand its history to this extent is just sad. The US was radically egalitarian at its founding and served as the example for the rest of the world for at least a century and a half.
John Adams: "I always consider the settlement of America as the opening of a grand scheme and design in Providence for the illumination and emancipation of the slavish part of mankind all over the earth."