Not disagreeing with you or parent in general, that a post (or as you point out a history of posts) can be personal data. What I'm saying is, in general it isn

Not disagreeing with you or parent in general, that a post (or as you point out a history of posts) can be personal data. What I'm saying is, in general it isn't. If you sign up to platform XYZ and make a post, in general, the content of the post is not personal data. It certainly can be. But by default it isn't. That's a misconception I want to dispel.