They didn’t say prescription drugs. OTC drugs are also drugs. (In fact, they’re the drugs the article is about!) And the majority of drugs are OTC drugs. I would fully believe that the majority of
OTC drugs do basically nothing.
(Consider: how many problems are there with your body that you’re actually likely to be able to solve with a drug that can be taken safely and correctly at basically any dose, basically any schedule, quitting whenever you like, and without checking for cross-drug interactions? Because those are the requirements for a drug to be OTC. There exist far more OTC drugs than there should, given the number of OTC-able problems, is what I’m saying.)