Saying that something offers hearing protection is a claim that it has been tested and shown to be effective at protecting the user's ears. Most earbud/headphone makers won't make such a claim because testing is expensive and anyway, that's not what the product is for. It's for listening to media. What is to prevent a user from cranking the music volume up too loud, damaging their hearing, and suing the device manufacturer because they claimed it was hearing "protection"?