> At least it can't be called a "horse dewormer".

The reference to "horse dewormer" is the fact that a substantial volume of people started actually ingesting horse dewormer bought straight from farm supply stores because ivermectin was listed as a component.

Demand for horse dewormer intended for this ad-hoc use grew so much that its availability was jeopardized, and in some cases ceased to be available to farmers who needed it to treat their cattle.