I've been thinking about this - whoever wrote it would have had it cleared by an Editor and Editors have to ensure the work represents the views of the Publisher - so the ultimate 'they' is presumably the Publisher.
Coincidentally, I was listening to a podcast just yesterday, and this subject was touched upon by a guy who follows a carnivorous diet and has apparently not brushed his teeth in ten years, and has no dental issues at all. The question was asked “when did you last see an animal in the wild brushing its teeth?”