I play both to be honest. Here is my warlock that I worked on, I also have a bunch of 15-20s on classic cause I like alts.
Do you realize, or even care, that post history isn’t tied to an account? So someone could easily get on four different toons of theirs both retail and classic, and troll anyone. So no, posting on your retail toon doesn’t mean much. They used to have it account wide and now its not.