Let's be specific then. Favoritism can prevent someone else's participation in a market, but they are not the same thing. Tax cuts are fiscal policy that benefit people with higher incomes. This sort of policy does not prevent anyone else's upward mobility nor does it prevent anyone else's participation in the market, but tax cuts do benefit some more than others, specifically rich people. If in your next post you continue with the definition of these words, i will ignore that part.
Legitimacy is a concept in political science which refers to people accepting being governed by a political body. This can be extracted either via respect or fear.
http://en.wikipedia.org/wiki/Legitimacy_(political)
As for your third paragraph: Your problem is that you think of the state as a monolithic entity that represents a single group and a single interest, and at the same time, you focus almost obsessively on the state as a means to express power, and pay little to no attention to the private sphere. You think of state as power, but you never give the same importance to the family, the church, the work place, and the media as means of power.
For you then, it's incomprehensible to see that for the black man the most visible oppression came (and to some extent still does) from daily private life. That for women, the most visible and inmediate oppressor was the husband. That for gays, lesbians, bisexuals and transexuals the inmediate and most pressing form of oppression came from private homophobic citizens in the shape of beatings and murders. And for you, because you see the state with a simple monolithic vision, and you see it as simply a tool for the stronger classes, it's incomprehensible to understand why the state would promote desegregation, promote abortion, why the state would attempt equal pay amendments, why the state would promote hate crime laws.
And your ideology, and others like it, whether on purpose or not, would seek to strip these groups of one of the means they have, and historically have had, to overcome both oppression from the state and oppression in private life. Is it really any surprise that most people who cling to anarcho capitalism and libertarianism are white, male, and more often than not, middle and upper class?
Furthermore, democratic representation and voting, as imperfect as it might be, is still far more egalitarian (one vote per person) than voting via the market place. Because in the market place, you vote with your wallet, but money is not distributed equally.