But they're selling things that aren't actually valid diagnostics as if they were diagnostic tests. In what sense is prohibiting that too stringent a regulation

But they're selling things that aren't actually valid diagnostics as if they were diagnostic tests. In what sense is prohibiting that too stringent a regulation? It's not DNA-specific; if you set up a random lab that claimed to diagnose diseases from blood samples that you invite people to mail in, your lab would be shut down pretty quickly if you never validated the analyses. If they want to sell DNA dumps and call them DNA dumps, that'd be truthful advertising. But if they want to make diagnostic claims, they need to actually back them up.