I think what the author misses is the large institutional structure that restricts the supply of experts and (as a result) enhances their prestige. These days, with the growing availability of technical information, existing systems of licensure, credentialing, and professionalization are breeding resentment on both sides of the lectern. The author's focus in the article is on the layman's resentment for the expert.…
I think this article is about laymen's tendency to overestimate their own knowledge of a particular subject (typically every subject), thus resisting the opinion of people with formal (or non) authority. I, for one, share the author's view on this phenomenon. In my opinion it is a wide spread issue, maybe even pandemic in proportions. When was the last time you heard somebody not having an opinion on a particular sub…
However, there is also a problem of misapplication of D-K. It is not always true (like all generalizations, it fails to give any sound basis for assessment of any particular individual); and it can be a pretext for smuggling other premises.
To try to explain the latter as briefly as possible, suppose there is a consensus of experts on proposition P, and critics C dispute P; then a speaker or writer denounces the criticism as an illustration of D-K, but maybe C are critiquing on the basis of some claim that is not refutable by the proponents' expertise - maybe that they have a conflict of interest, or are talking outside their area or expertise.