Honestly…people who toss out the whole “horse dewormer” talking point should also refuse to take penicillin if your doctor prescribed it because they also give that drug to horses too.
It’s not just a “horse dewormer” folks, it’s a “people dewormer” that has also been used in anti-viral treatments as well. Argue that’s it’s not effective, but stop pretending that this isn’t a drug that is prescribed to people all over the world.