The EFF has a good guide about the relevant laws: https://clinic.cyber.harvard.edu/wp-content/uploads/2020/10/...
This "manufacturer" is not doing its due diligence in any way, shape, or form. They are the ones who should face jail time for not implementing bare minimum security practices.
The idea that the guy revealing a complete lack of security is committing a crime is like saying a guy informing someone that they're naked is guilty of forcibly stripping that person. Or that telling someone there's a giant red button that drains the landlord's bank account is guilty of pressing it. Maybe they should remove the giant red button?! Or at least put it in a locked room?
We should also, as you point out, require vendors to implement minimum security standards.