Also, at the bottom of your link it says "FDA Regulations per 21 C.F.R. Sec 874.3300" I don't know if that's the same as the legislation I posted above or the one that allows hearing assisting devices - not hearing aids - to be sold
The over-the-counter aids are just for people with mild hearing loss. Hopefully if someone buys one and it doesn't help they'll realize that they need to see an audiologist or hearing instrument specialist.