The FDA has said multiple times that Ivermectin is not approved for human use and it can be dangerous in large doses. The agency added that “animal drugs are often highly concentrated because they are used for large annuals like horses and cows, which weigh a lot more than we do — a ton or more. Such high doses can be highly toxic in humans.” The final paragraph explains the problem pretty well. Some might, or they are, taking larger doses than intended for humans. That's human error and not a reason to try to scare everyone away from a drug that's proven beneficial in many parts of the world.