Pure capitalism (read: not what we have today) is quite innocuous. The danger with capitalism comes when it mingles with government. If a corporation can influence the government to pass laws that benefit that corporation at the expense of another entity, it can become extremely harmful, and allow that corporation to grow far more powerful than would otherwise be possible. The United States is a prime example of the dangers of capitalism mixing with government. It's not unlike the dangers of religion mixing with government- when a single religion controls a government, it inevitably leads to intolerance and in the end- violence and paranoia toward those who don't comply. A pure capitalistic system (no laws governing business whatsoever) is the only ideology that allows other ideologies to coexist with it peacefully. If you have communism or socialism, your belongings are forcibly taken from you and given to others who did not earn them, or wasted through government. In a pure capitalist system, your belongings are your own, to do with as you wish- and you can choose to form a socialist or communist sub-group voluntarily if that suits your interest. That's the only way ethics can be preserved in society.