As for the not-understanding-it part, how is it hard to understand? It's effective marketing. The industry doesn't make money by people getting better, it makes money by getting (their) drugs into them. Humans are a vehicle for the delivery of their product. (So now are pets. The opening of the pet market for antidepressants is so classic a move that it will surely be studied in business schools.)

The vegetable oil industry did the same thing, ingeniously, against dairy fat. Remember those decades of propaganda about how butter and cream mean cholestorol which means heart attacks which mean death? It was an industry contrivance. The original studies it was based on were shamelessly cherry-picked. The campaign leveraged the widespread public fear that derived from the heart-attack epidemic of the 1950s and 60s. (Edit: I learned this from a CBC Ideas episode a few years ago.)