And some are anarchists.
In economics, control over the basic infrastructure needed to run society - to grow food, to produce goods, to maintain transport - is concentrated into the hands of a minority of people. The majority of society is thus forced to sell its labour to this minority in exchange for what they need to survive. This minority of people, meanwhile, gains enormous profits and is able to make decisions affecting large sections of society in order to gain more. Under this economic system, capitalism, the pursuit of profit takes precedence over other concerns in order for business to survive, and as such leads to exploitation and domination of the majority of people in pursuit of this aim.
In politics, power remains concentrated into the hands of relatively few. In part this is due to the relation of politics and economics - businesses weild enormous power over the government, both through official means such as international trade agreements and unofficial means such as party donations, threats to withdraw, and so on. Within government, decisions are made by a tiny number of people supposedly "representing" the interests of their constituents. Once in power, other factors - influence from business, the need to maintain power, individual agendas, incomplete information - mean that even the best-intended politician would be woefully incapable of truly representing the interests of "their" constituents. Historically, however, even this degree of popular participation has not been the norm.
Another, largely unexplored, area in which power may be seen as corruptive could be described as the "spiritual" or "moral." The concentration of moral power, the authority to declare what is right and what is wrong, what is godly and what is of the devil, is as corruptive and open to abuse as any more material power. History is filled with examples of divinely-sanctioned wars, almost universally fought for material causes - a clash of one power bloc with another, a conflict for this or that resource - but given popular support as a consequence of a blessing from a religious leader in whom the people have faith. When the ability to declare what is right and wrong is placed in the hands of an individual or group, simple human fallibility dictates that this will be taken advantage of in the pursuit of some goal.
Nowhere is this more starkly obvious than in the twisted world of cults such as the Church of Scientology. L Ron Hubbard, the Source and discoverer of the "tech" had an insight above and beyond that of the everyday person. His understanding of the world enabled him to see things others could not, and what he decreed became policy. And so when he declared that enemies of the Church could be "sued, tricked, lied to or destroyed," when that policy was applied to Paulette Cooper in a bid to drive her insane, when the cult infiltrated the United States government - all of these things were ethical because Hubbard said they were ethical. With Hubbard gone, the cult continues to enact his teachings, and so their continued coverups, intimidation, harassment and deception are held as morally acceptable, because it's what Ron would have done.
When any person is given the authority to dictate to another what is right or wrong, ethical or unethical, the scope for abuse is enormous. And like any other form of power, where the potential for abuse exists, those most likely to abuse it will be the most attracted.
Temple of Xenu