The danger was not that the medicine itself, but the fact that it was a) unproven to have any effect, b) often taken in horse doses causing nasty side effects (because horse medicine if often good enough for human consumption, even if it's not held to the same standard) and above all c) seen as an alternative to proper measures like vaccination, masks, the whole ordeal.
It's a pretty good way to get rid of parasites, but the association with COVID caused a lot of problems.
It's a pretty good way to get rid of parasites, but the association with COVID caused a lot of problems.