Do you think he's pessimistic about people? I think that like (almost) any economist I can think of, he believes that people can do pretty well anything they put their minds to, and in particular through voluntary co-operation if it's not something possible for one person alone. He bemoans the propensity of humanity to hand itself over to be governed more or less coercively. And has a particular sore spot for people who seek power over others (which is right - insofar as one has power over another one impinges on the other's liberties to a greater or lesser extent) - even where they do not know or acknowledge that they seek or hold power.