At their very simplest, anarchist beliefs turn on to two elementary assumptions. The first is that human beings are, under ordinary circumstances, about as reasonable and decent as they are allowed to be, and can organize themselves and their communities without needing to be told how. The second is that power corrupts. Most of all, anarchism is just a matter of having the courage to take the simple principles of common decency that we all live by, and to follow them through to their logical conclusions. Odd though this may seem, in most important ways you are probably already an anarchist — you just don’t realize it.
Most anarchists start with beliefs like these ime. He makes a kind of naive argument using the socratic method, as pro-state beliefs mostly appear when asking questions about coordinating at scale, but he takes a small stab at that near the end:
Now, you might object that all this is well and good as a way for small groups of people to get on with each other, but managing a city, or a country, is an entirely different matter. And of course there is something to this. Even if you decentralize society and put as much power as possible in the hands of small communities, there will still be plenty of things that need to be coordinated, from running railroads to deciding on directions for medical research. But just because something is complicated does not mean there is no way to do it democratically. It would just be complicated. In fact, anarchists have all sorts of different ideas and visions about how a complex society might manage itself. To explain them though would go far beyond the scope of a little introductory text like this. Suffice it to say, first of all, that a lot of people have spent a lot of time coming up with models for how a really democratic, healthy society might work; but second, and just as importantly, no anarchist claims to have a perfect blueprint. The last thing we want is to impose prefab models on society anyway. The truth is we probably can’t even imagine half the problems that will come up when we try to create a democratic society; still, we’re confident that, human ingenuity being what it is, such problems can always be solved, so long as it is in the spirit of our basic principles — which are, in the final analysis, simply the principles of fundamental human decency.
Anarchism working at scale seems undecided to me. One thing I am decided on, however, is that better coordination tech will make scaling anarchism better whether anarchism is feasible today or not.