It's very natural for humans to join together in groups and to cooperate and compete with outsiders. Shall, and can, we outlaw that?
Some people have more skill and knowledge and are natural born leaders. Others enjoy being followers. If people voluntarily form such an organization (religions or clubs, for example), and if that organization gains some power, can and should we stop them?
Moreover, how would we stop them???
The very notion of "outlawing tyranny" implies a force (the state?) to enforce the law. In other words, anarchism opposes tyranny, but don't we need a state or other authority to stop tyranny?
Maybe the idea behind anarchism is that the great mass of people will agree to stop them. So the force needed to stop cheaters and criminals will be based on consensus, not on hierarchy. Does this imply a common militia? Everyone carries a gun? The NRA would like that. Isn't it natural to have a government that serves the people and ensure the common good? That is, rather than having everyone do police work and enforce laws -- there are laws, right? -- the people delegate those responsibilities to specialists: the government.
Furthermore, corporations are often innovative and efficient, or at least effective, at producing complex products and services (e.g., Microsoft, Boeing, Intel, Google, and Toyota). Likewise, universities and the sciences are pretty hierarchical. Those who publish papers and survive peer review gain power and get to decide which other people are allowed into the community. It's competitive and rather brutal. That's how science progresses.
Moreover, some corporations are pretty damn good: CredoMobile supports progressive causes, for example. Many corporations pay their taxes and make an effort to be decent. The blanket condemnation of corporations is extreme. When corporations are regulated and taxed they are useful.
Can non-hierarchical firms produce complex products efficiently? Are there examples of that?
Yes, there are such examples. Open source software is of high quality and is widely used; a prime example is the operating system linux. There's also gnu, Open/Libre Office, and The Apache Software Foundation. Many businesses rely on free open-source software (e.g., Java).
Gal Alperovitz has written about the movement in the US towards cooperatives, worker-owned companies, and small businesses, in What Then Must We Do -- Straight Talk about the Next American Revolution, and in other publications.
I am all in favor of such local, community-sourced, worker-owned, nonprofit, and non-hierarchical organizations. And I agree with anarchists (and those libertarians who aren't in it just for the money) that tyrannical government programs and should be done away with. What I disagree about is whether we should also do away with the non-tyrannical, constructive government programs such as Social Security, Medicare, public education, and public transportation. The question is: do we want to discourage government in its entirety?
I also don't believe it's possible or even desirable to stop corporations from forming, especially not without government. We do need to regulate the corporations, however.
Several paragraphs above I wrote that anarchists want to replace government and corporations with cooperative, local, worker-owned/managed ventures. How about publicly-owned ventures? Presumably not, because publicly owned ventures would seem to imply the existence of a government. Alperovitz is most excited about worker-owned cooperatives and firms , but he also favors publicly owned enterprises and institutions
Next question: in worker-owned cooperatives, is there no hierarchy? Incompetent or nasty workers need to get kicked out. I presume hiring and firing are a group decision. That was the method described in Shift Change: a film about employee owned cooperative businesses. The cooperative they highlighted had rules for becoming a member; people could apply, after a probationary period. That's a flat hierarchy, I suppose, but it's still susceptible to corruption and power-grabbing, if people are denied membership, or services, for the wrong reason.
Tryanny is possible by the group (by the majority, or by worker-owned firms), and not just by the government.Government's regulatory functions
In the previous section I talked about the productive effects of corporations: they produce goods and services. But of course, corporations are often very harmful: e.g., war-mongering by military contractors, death-selling by cigarette manufacturers, toxic food by Monsanto, denial of global warming by oil companies, price fixing by Big Pharma, pollution, fraud, corruption of government, political campaign spending, tax avoidance, bailouts, subsidies, etc.