There is an entire subculture of people drinking bleach and taking horse dewormer and swallowing Alex Jones magic brain pills daily. It’s a huge money making venture for some of the worst people in society.
A surprisingly large amount of US-Americans do have intestinal parasites and probably would benefit from a round of Ivermectin. If it was sold over the counter like in certain presumably less developed countries, maybe people would prefer not to purchase the veterinary version.