You misunderstand defined's post. He's not saying that ZATAOMM is a high quality book, because the author was obsessed with ensuring that his book was of high quality. If that was the case, you would be (mostly) right, as there is a subjective aspect to determining quality.

No.

ZATAOMM is a book about the philosophical concept of "Quality". What is "Quality"? What do we mean when we say the word "quality"? How does that understanding, or lack thereof, impact our life, sciences, and society?

That is what defined meant. Read with that understanding, defined's statement reads:

I believe ZATAOMM is a work of genius, that was only possible due to the author's obsession with learning everything he could about the topic of the book before writing it.

Thank you for explaining that. You are exactly right.

I really should have spelled it Quality, to show that I meant the philosophy of Quality rather than its more mundane interpretation.

At the same time, in an interview with Pirsig that I read somewhere, IIRC he did rather archly claim something to the effect that the book had better be high quality, considering its subject matter.

I tried to find that interview, but could only come up with this piece [1].

[1]: https://www.theguardian.com/books/2006/nov/19/fiction

>Quality is totally subjective.

No, it's not. That's just an American prejudice about it, because the individual there is always king, even if they are as crude as they go...