Because the scammers sold it as being a miracle cure, and the idiots literally ate it up and declared that the fact they were losing their stomach linings due to ingesting what were horse dosages was a good thing?
Is that a sentence you expect me to seriously respond to?
It's a drug that is safe for humans when prescribed by a Doctor. Period. There were some studies during Covid that suggested it might be helpful as a treatment, so some people were prescribed it by their Doctors given how cheap it and readily available it is. Perfectly sensible. Just because some people did what you suggested doesn't mean a thing.
You can have something licenced for a specific use in humans and for it to be extremely unsafe to then use the same stuff in the way you would for any other animal, let alone taking the dosage intended for a large animal.
No one ever suggested taking it at stupidly high doses, is your reasoning for Ivermectin being unsafe because "some people lost their stomach linings due to ingesting high doses"? lol. This is laughable. It's a perfectly safe drug for humans to take when prescribed at doses suitable for humans, like almost any other drug or substance. I can go drink 12 litres of water and be in hospital, it doesn't say anything about water being unsafe.