This engendered a barrage of more or less agitated rebuttals with titles such as: "Do not throw equations out with the theory bathwater," "Mathematical illiteracy impedes progress in biology," "A suggestion on improving mathematically heavy papers," and "No evidence that equations cause impeded communication among biologists." Anyway, an alternative view is that theoretical papers (with lots of equations) are mostly cited in other theoretical papers, although this sounds obvious and would never have been published in PNAS.
I would wager that the same is true in all fields: Physiologists certainly cite other physiologists more often than they cite clinical scientists (and almost never cite mathematical biologists). It is further easy to extrapolate to the conclusion that detailed physiological data in a paper is associated with fewer citations in clinical medical journals. The obvious interpretation is that overzealous use of physiology in articles impairs dissemination of medical science, and that physiologists should use more common words and talk more about patient-survival and quality-of-life in the same way that mathematical biologists should relegate their equations to the appendix. The idea that they might be comparing apples to oranges (clearly a biological concept) is not even discussed in the paper, which makes the discussion a bit lopsided. More as if they were writing an opinion-piece than an article on empirical science.