Unproven doesn’t mean ineffective. Cranberry juice isn’t FDA approved to help with urinary tract infections, but is frequently recommended by urologists and works. Another example is that isopropyl alcohol, which is an effective disinfectant, doesn’t meet the EPA standards for being a pesticide… which is because it’s existence predates the process.

It’s expensive to go through that rigorous process, and there’s no economic incentive to go through that for something that isn’t patentable. In the case of cranberry juice, it’s not sold as medicine. In the case of alcohol, you can buy very expensive wipes that have a certification if you need it for some industrial process.