I believe he is warning against the Coffee Shop fallacy. IE, you may like coffee, but if you think running a coffee shop is a good way to enjoy/experience coffee, you are unlikely to be in business long.
It also seems like he's saying that "code" as an aesthetic principle is a very small part of your business. Your code is a means to an end (for your users), and does/should not hold much of your attention as an intrinsic ideal.
Excellent mention of the coffee shop fallacy. I think you nailed the point perfectly. Coffee making is only 5% of running a coffee shop. Dealing with customers (i.e. sales and marketing) is the majority of the work. People can get coffee anywhere; they go to your shop because of the perceived value of your product. Coffee (and code) becomes a commodity. While there is some really brilliant artisanal coffee (and code,) the general public doesn't usually know enough to tell the difference.
It also seems like he's saying that "code" as an aesthetic principle is a very small part of your business. Your code is a means to an end (for your users), and does/should not hold much of your attention as an intrinsic ideal.