This man was in fact an excellent editor, smart, hardheaded, with a good design sense. But this very obvious flattery penetrated his defenses like the proverbial knife through butter. I think today such straight-out flattery is rarer than it was back then. We are subtler about flattery. We are warier about being detected.
Bystanders are more cynical.
We don't want to seem too earnest. These days, we tend to think of all praise as flattery. We rarely bother trying to distinguish between the two. Praise seems to have become a subset of flattery. Flattery has never been a flattering idea, but now our slightly jaundiced, strategic view of it has tainted ordinary praise.