I don't get that interpretation from that quote at all. To me, the quote is about contrasting the speaker's subjective view with a more objective "standard" requirement for a PhD degree. It's basically saying: "To me, his work as that of a genius. But YMMV. However, even if you don't want to go quite that far, you'll certainly admit that it's great and fulfills the requirements for a PhD."
Not being the work of a genius does not necessarily mean that it's not an achievement.
I think it's more along the lines of: the degree itself is a insignificant and unworthy of his work. It's like giving him a Kindergarten gold star sticker. Which says something about the quality of his work, or of other degree holders, or both.
I don't get that interpretation from that quote at all. To me, the quote is about contrasting the speaker's subjective view with a more objective "standard" requirement for a PhD degree. It's basically saying: "To me, his work as that of a genius. But YMMV. However, even if you don't want to go quite that far, you'll certainly admit that it's great and fulfills the requirements for a PhD."
Not being the work of a genius does not necessarily mean that it's not an achievement.