The main way that capitalists have always formed the dominant class in the US is with the power that their money gives them. With their huge concentrations of money they control how elections are conducted: how candidates are selected and backed with money, how political parties are funded, how mainstream media shapes the information about these candidates, and how other people are shut out of the political process.
But this election season offered a rare new candidate, Donald Trump, who was not under the control of the current directors of the ruling capitalist class. This candidate had accumulated his own pile of money while playing in the game of capitalism. And, what he says is not carefully scripted by these directors, and mainstream media which is owned and controlled by the capitalist directorate doesn't like his maverick ways, and especially does not like the way Trump often challenges their lies. Watch the 12:40m video in the article to see an illustration of this.
Vulgar, crude, racist and ultra-sexist though he is, Donald Trump can still see how awful the American mainstream media is.