It happens in films too. Example: The very first scene of Spider-Man: Homecoming - an otherwise entertaining film - features an exchange between two characters, one of whom refers to drawing cowboys and Indians as a child. The other character replies: "Actually it's Native Americans" in a sanctimonious, irrelevant, entirely out-of-character moment. Why include this bit at all? The film isn't about Native American injustices, etc. This is simply a person speaking in character, and he doesn't need to have someone (in an out of character moment) correct his politically incorrect terminology (and by extension, finger-wag the audience). It drives me mad, and I'd love to snip it out of the film as it adds absolutely nothing but condescension. Why the hell open the film with this?

Here's the clip: https://www.youtube.com/watch?v=rcBzXxW-aj4