Making this a privacy issue is about a decade PR two early.

These devices require a surgical implant and extensive training. There's no "thoughtcrime" potential here. This of for giving paraplegic people, victims of neurological disease, and potentially non-verbal autistic people the ability to speak.

The need to use a "public thought password" is because the AI training and system is not good enough yet to recognize the difference between internal monologue and thoughts directed for others. Likely because people involved in the research have been rendered mute for AI long they don't know the difference anymore either.

Sure, it means both come from the same source and both can be translated. But in some SciFi future world where the cops plonk a thought helmet on you, just do what I do all the time anyway, and think "boobs boobs boobs..." over and over.