The problem with power is that... well... it's POWERFUL. It can be used for both good and ill, but regardless of it's usage, the more power there is behind a command, the harder it is for the individual to resist. That's pretty close to the definition of power.
It's become clear that throughout history there are some people who are driven to accumulate power. It's also become clear that there is no correlation between a person's ability to accumulate power and his/her desire to use it to benefit mankind. Certainly there have been examples of power being used very wisely, and for the benefit of man -- but there more than numerous regrettable examples.
The Libertarian viewpoint is that the only way to prevent these tragedies is to prevent the accumulation of power. We believe that all power originates from the people as individuals, thus governments and corporations only acquire power by a lessening of the power of the people. If government's sole purpose becomes to protect civil rights and to preserve the power of the people above government and corporations, government immediately becomes more honest. If government no longer has the ability to help corporations make laws against the people, corporations will have no reason to try to influence government.
I think that man has a natural inclination to accumulate power, and power positively reinforces the people who accumulate it. It seems to me (and most libertarians) that the only way to stop people from accumulating power is to cut off the source of the power. That can only be done by refusing to allow people to yield their rights, and refusing to allow governments or corporations to curtail the rights of the people.
Will this hinder our ability to do great good deeds and achieve mighty milestones? Somewhat. People can still come together in free associations. Polio was defeated by just such an organization when the March of Dimes rallied the country and found a cure.
Will it also stop the misappropriation of power? I believe so. And that is a benefit that is worthwhile.