It's also governments who choose to allow this to be legally done. Nobody allows homeopathic gas stations that look like the real ones.
Nearly every market where the quality or efficacy of the product isn't readily verifiable by the purchaser is a hotbed for scams and snake oil.
We allow gas stations to have diesel pumps right next to gasoline ones. We just require that they be labeled appropriately and its expected that people read the label and not make assumptions based off proximity.
OTC medical matter isn’t regulated anywhere as tightly as active drugs. They’re supplements or food additives or other such things. Whole lot of that shelf space goes to stuff that’s not as useful or desirable as people think. And any ambiguity is naturally exploited to the max.