[Yes, I, too, am going to focus on the billionaire part; I'm not going to be applying to YC for anything anytime soon. I don't need to know how to navigate their interviews.]
I would like to make a minor note: the thing that politicians sometimes say is, "that the only way to become a billionaire is by exploiting people". Not "setting out to exploit people", not by trying to be Snidely Whiplash the professional mustache twirler. The statement is about effects, not intentions.
Henry Ford started out building cars, not controlling people's lives. But that's kind of what he ended up doing (https://jalopnik.com/when-henry-fords-benevolent-secret-poli...). Andrew Carnegie wanted to make steel but also got the Homestead Strike (https://en.wikipedia.org/wiki/Homestead_strike) (involving the Pinkerton Agency mentioned the other day).
But look at some of the names mentioned in the article:
* Apple started to make computers and related gear, and did so very successfully. On the other hand, it might be reasonable to see Steve Wozniak as exploited, not to mention the other early employees. And then there was that Foxconn thing....
* Mark Zuckerberg did indeed want to "engage online with his college friends". He did not start out wanting to dick around with democracy as we know it.
* Larry and Sergey certainly wanted to search the Internet. But then they bought DoubleClick, one of the most loathed companies on said Internet, and turned it into one of the world's largest cash cows, primarily using their ability to collect information on everyone, everywhere.
* AirBnB absolutely, positively did not set out to violate hospitality laws and do weird things to real estate worldwide.
* Paul Graham, of course, got started by selling Viaweb for $49 million of Yahoo stock. Viaweb had 21 employees at that time (https://www.nytimes.com/1998/06/09/business/company-news-yah... anyone know how the other 18 people made out? And that leads me to YC itself, which gives money to start-ups in exchange for...something, and which helps introduce start-ups to other investors. Which has never, ever, in the history of the world resulted in exploitative relationships. (I'm being sarcastic. It's not hard to find companies whose founders have been forced out by investors, much less other kinds of interference.)
Which is why Paul's argument about billionaires is a strawman. I firmly believe him when he writes, "[Working because there's nothing else they'd rather do], not exploiting people, is the defining quality of people who become billionaires from starting companies." And I believe that "Y Combinator certainly sees founders whose m.o. is to exploit people." They exist, and I believe YC rejects them. But none of that has anything to do with the path from there to billionaire-hood. There is a billion decisions between founding and billionaire-osity, and some of them, historically, involve stepping on someone.
Because Paul doesn't seem to want to acknowledge that, I get worried when he writes about "I think they start from the feeling that it's wrong that one person could have so much more money than another. It's understandable where that feeling comes from. ... The mistake they make is to jump from feeling bad that some people are much richer than others to the conclusion that there's no legitimate way to make a very large amount of money." Money is power, but I suspect Paul would be less happy (publicly) making that statement with the substitution. (And of course there's legitimate ways to make large amounts of money; the powerful define what is legitimate.)
This is getting too long, so I'll just end it with some snark:
Here is a very American statement: "There are certainly some people who become rich by doing bad things. But there are also plenty of people who behave badly and don't make that much from it. There is no correlation — in fact, probably an inverse correlation — between how badly you behave and how much money you make." Yes, right up there with "I'm a temporarily distressed billionaire myself": money is correlated with morality.
"Can you imagine a better way to destroy social mobility than by telling poor kids that the way to get rich is by exploiting people, while the rich kids know, from having watched the preceding generation do it, how it's really done?" -- I'd imagine poor kids already know about exploiting people. They just don't have the contacts to do it correctly.