It is labeled for horses primarily. Approved for and customarily used on animals first. You know, humans don't get many worms where the drug was invented and made. It's like, some adults wear diapers, but when someone says diapers the user you picture is a baby. You say Ivermectin, and anyone that knows anything about it thinks horses. It's used by vets more than doctors. It's available, I believe, over the counter, at farm supply stores. Humans require a prescription, in the US, anyway.
Sometimes public ridicule is an appropriate remedy when social conduct is harmful yet not illegal.
In context, Mary Mallon was medically quarantined against her will, for life, because she refused to stop knowingly spreading disease. She broke the social contract. The social contract requires basic personal hygiene. The horse paste people anti-mask types are breaking the contract; they waste medication, they take up medical resources, and they knowingly spread disease. The same people take huge dumps and then don't wash their hands.
And now, some Shakespeare:
"All the contagion of the south light on you, You shames of Rome! you herd of--boils and plagues. Plaster you o'er, that you may be abhorr'd. [Now go], further than [can be] seen, and one infect another, [and then go] against the wind [another] mile!"