This is not mine, and I do not consider myself to be particularly knowledgeable on this topic. Though my understanding is that it's a theory of no rulers/hierarchy with an emphasis on direct democracy rather than something resembling Hobbes's State of Nature. I'll do my best to add to the discussion!

And if I of all people can't consistently behave reasonably, how can I expect it from the rest of you dumbfucks

If you don't expect others to behave reasonably, then that's a good argument for getting rid of hierarchies where other people hold power over you. If power corrupts is a statement you agree with, then we shouldn't be rewarding those who make a career out of seeking power. The difference is without structures of hierarchy, the damage of unreasonable people will never reach that which could be caused by a political or corporate leader with power over thousands or even millions.

Without specific ethical training, most people do not consider the effects of their actions on others, especially among equals

I didn't read this the same way - I think the point is that people can organise to meet their needs between each other directly. I don't believe the claim was that without hierarchy, people will magically be flawless and university good to each other. As a side note, I do believe that people are generally better to each other when their needs are met, which is a current issue with the political structures and concentration of wealth we have today.

I'm curious to hear more informed discussion about the fair points you brought up, and a quick search returned https://lemmy.ml/c/anarchism. Feel free to ask those questions there! In particular, I don't know much about the lawyer part you mentioned.