My point was not that they should talk about the Holy Roman Empire with their family, but that they shouldn't share information with strangers that they wouldn't share with their family.
If you don't want your family to know something, you shouldn't tell it to OpenAI either.
The reason you wouldn't say something to someone is because you are afraid of the power that you give people along with that knowledge.
Your family is in a a position of power, which is why it can be scary to share information with them. People at OpenAI are also at a position of power, but people who use their services seem to forget that, since they're talking to them through a computer that automatically responds.
This is silly. It's not like OpenAI is going to find your family's contact info, then personally contact them and show them what you've been talking about with ChatGPT. It's just like another post here comparing this to writing a post on /r/relationshipadvice with very personal relationship details: the family members are extremely unlikely to ever see that post, the post is under a pseudonym (and probably a throwaway too), and the likelihood that someone is going to figure out the identity of the poster and seek out their family members to show the post to them is astronomical.
If you don't want your family to know something, you shouldn't tell it to OpenAI either.