For clarity, I'm a former anarchist, now Marxist-Leninist (have been ML for years, my anarchist days are a good while ago). That's going to color my disagreements, and Roderic Day as an ML's as well.

I disagree that the state exists to "concentrate power," as in accumulate more and more power. The state instead exists to protect the ruling class of a given society. This coincides with the formation of states historically, as they arose as class society arose. From that point, I also disagree with the notion that serving ones own class interests necessitates corruption. If the proletariat holds power over the state and uses it in its own interests, then this is both logical and a good thing. In China, for example, after the proletariat took power and wielded the state against the landlords and existing capitalists, life expectancy doubled:

This is why class analysis is so important. In socialist states, throughout history, life expectancies, literacy rates, democratization, the rights of women, education and healthcare guarantees, and more have all skyrocketed. The violence that comes from revolution and protecting the revolution isn't because the proletariat used states to do so, but instead because class struggle does not cease overnight. Corruption exists into socialism, but this is not an insurmountable obstacle, and is instead something a healthy socialist state must keep in check, same as any other societal problem, as the state withers away gradually.

The author isn't suggesting that people's way of thought isn't colored by how they live and exist, but rather that this is essential to understanding this. You can spread ideas, but you cannot "brainwash" people, for good or bad. They have to realize their own class interests to avoid falling into false consciousness, and this can be agitated for by those of us that have already undergone transformations (forever incomplete, and always transforming) in how we think. We have to bring people over.