I think the author’s central point is that money can be viewed as an IOU for future utility from society. If I view all of society outside the individual as one

I think the author’s central point is that money can be viewed as an IOU for future utility from society. If I view all of society outside the individual as one agent, say a giant company that owns the stores you shop in and still employed you, and that company pays you $COMPANY-BUCKS to be redeemed at the company store, they got utilty out of you for nothing until you redeem the company bucks for something. The author is saying that accumulating wealth is just, assuming you were payed fairly, showing a debt society has taken on to you. Society hasn’t had to produce something in return yet. And it’s how you spend that debt that can cause problems, not that the debt exists. You can spend it in ways that direct people to create utility that you share with society or in ways that lock that utility up.