The presumption here is that email(electronic communications) are necessarily a debased form of writing -- rather than today's state of the art. Academics, on the other hand, are notoriously poor communicators -- thinking that the purpose of all communications (as with everything else they do), is to impress, intimidate and control -- and so they are overly concerned that their reader get their manipulations right.
With real communications, there is an understanding that both the speaker and the listener co-create the communication -- rather than that one control the other, and thus have to use techniques like emoticons to tell the reader when to laugh, or that their hostility was not intended, etc.
But in emails (electronic communications) that are the state of the art, the writer has the ability to communicate well and the recipient has enhanced abilities to interpret the intent. So the presumption of their understanding that emails are less effective rather than supremely effective beyond their imagination, is only a projection of their own inabilities to effectively communicate, instead of being an inherent limitation of the medium (genre).
Those are the presumptions of the old mass media mind -- rather than that the "other" may actually have a superior capacity to understand.
I have always thought that we might communicate more in email than face to face. It's sometimes easier to put things into words when the person is not 'there'.