It seems like you are actually agreeing with Paul Graham. You see the concentration of political power and the resulting erosion of the middle class, and you want to fix them. Great! Those are the kind of "bad" sources of inequality the original article is talking about.

Paul doesn't want to ignore these problems, he just wants to call them what they are. The only problem I see is that we don't have a good term to cover all these related concepts. Alternatives like "creeping feudalism" don't have the same ring as "inequality", even if they may be more accurate.