> have lived alongside us (or vice versa) for centuries if not millennia
Without addressing the overall point, I don't understand this sort of argument for drug legalization, which I hear occasionally. Almost everything on earth has lived alongside us for 200,000 years, but does that affect safety and efficacy? Should we treat people with polonium? Bleed them with leaches? Burn them with fire to get out the bad parts? Eye of newt and toe of frog? I'm not comparing the OP's treatments to those things, I'm saying that being 'natural' isn't correlated with efficacy or safety.
Someone said to me recently that there was no point to vaccinations and masks because 'you can't stop nature'. I stop nature pretty well: I stop 'natural' thermodynamics with my insulated clothes and home, I stop entropy by eating, I stop gravity with a parachute and e. coli with a clean food supply. Sure, eventually I'll die, but not today.