No room for improvement?

This comes from a New York Times "The Ethicist" column that I can't seem to track down. The final line is the reason I'm sharing it:

A Bonus Question: "A few years ago, my friend of many years self-published a work of fiction and asked me to buy a copy and review it on Amazon. Reading this book was absolute torture, but I could not bring myself to tell her. Because of our friendship, and the fact that I’m an emotional coward, I wrote a positive review of this horrible book, at some cost to my self-respect. Now she wants me to read and review her second attempt at literature. What to do? — Name Withheld"

From the Ethicist:

This is someone whose friendship you value and whose literary efforts you do not. Being mindful of her feelings isn’t just cowardice; it’s also caring. So find a way to combine a measure of candor with a measure of kindness. That might be some version of: “Personally, I struggled to connect with this story, so I’m not the right person to post a review — but I’m so impressed with your creativity and dedication.” Otherwise you could take inspiration from Muriel Spark’s novel “A Far Cry From Kensington.” It features a book editor who, asked to assess an awful manuscript that her boss has already committed to publish, responds simply, “I consider that it cannot be improved upon.”