As for the overall issue of "Talking your position" - everyone does it. Left and Right leaning economists get different research conclusions. You just have to be aware that it exists. And despite this, the advice from PG, Peter Theil, Marc A and others is different, despite them all being long startups.
The article and some of the comments here seem to suggest that there's something more "authentic" about a piece when it comes from a subversive, low-power position. Why? What makes the perspective of someone in a position without power more authentic than the perspective of someone with it, other than the fact that it will probably resonate more with the personal experiences of many more people since power tends to be a pyramid with a much wider base than top?
The real answer is to carefully consider where the perspective of whomever is speaking is coming from, and identify how closely it aligns with where you are and want to go. The perspective of a billionaire on how hard it is to make ends meet, if you're living at the poverty threshold? Probably not that relevant. The perspective of a billionaire who started out poor on how he got to where he is? Probably pretty relevant.
Well someone not in a position of authority or power doesn't have to worry about losing said authority. If you tell too many uncomfortable truths or offend the wrong people, you may in certain instances loose some of your power. So it makes sense that the likely hood of getting an "authentic" story seems to get less and less as the person telling it rises in stature, power, authority.
General conservatism. People who have something to lose, be it money, fame, power, prestige, credibility, etc., will always weigh the benefits of their actions against the cost of losing what they have.
And they should. People with power are taken more seriously. Guys like Buffet can move the markets just by talking. But I think sometimes people don't WANT that kind of power/leverage when they write; maybe they just want to explore ideas, write for entertainment, or something else without all the hassle and baggage that status brings.
The halo effect. [0]
Or to put it another way - cynical psychology.
On the other hand, depending on how PG views his writing oeuvre, if he wants to be taken seriously as an essayist outside of the domain of business advice I could see it being in his best interest to write under a pseudonym. For better or worse most people are going to see him as Paul Graham startup investor/former startup founder. If he wants people to take writer Paul Graham very seriously, like Paris Review seriously, it would probably help to divorce himself as an author from his business background.
http://www.motherjones.com/kevin-drum/2014/12/economists-are...
I may have made mistakes in resizing it though.
I.e., the ideology of the study's author gives you very little information about the numerical values in the study.
http://fivethirtyeight.com/features/economists-arent-as-nonp...
It is very hard to not introduce bias into social sciences. This is also why psychology and software engineering studies are hard to trust. It is more pervasive in economics when there are rewards to be linked to a given worldview. (You can make a lot of side money as an expert witness if you have written a lot of papers either solidly pro or against anti-trust legislation)
Part of the point of writing essays is to explore ideas honestly, and honesty is often not safe. I hope he stays honest.
necessity as they say is the mother of invention. money is the mother of indolence and sloth. hence the essay. The issue about mixed motives is also tied in their somewhere, too. honesty comes more freely to those with nothing to lose. whilst those with everything to lose, have averything to gain from shading the truth. {etc}