Perhaps you misunderstood my quotes around approve. Literally, the FDA does not formally sanction the use of over the counter products other than making sure they do no harm.
The FDA does not "approve" products. The leave it to individual companies to provide the safety information and the onus is on the companies themselves. Companies cannot boast health benefits of their products. That the FDA sends letter out to the companies to cease or their product will be pulled.
It would be nice if there was a true approval system to determine effectiveness but that would be very very costly. So the FDA focuses on approval of drugs/medications which are more likely to do great harm. That process take years as drugs must go through clinical trials of larger and larger test populations.