Is that really the argument? Imagine if this is taking to it's logical conclusion and everything "not necessary for the plot" is removed from TV shows and movies. What's the point then? There would be zero point in watching the show or movie, reading the plot summary would serve the exact same purpose.

Movies and TV series are supposed to be a form of entertainment and even art on occassion, that takes you on a journey, makes you feel something. That involves many things that don't necessarily advance the plot, but get the audience emotionally invested into the characters, the fictional world, the narratives, the motives. Without that, what is the point? The plot can't exist on its own as a standalone entity. In many cases it even works in an inverse. The plot is used and chosen to make the audience feel a certain way about something. The plot becomes secondary to the same emotions the authors or producers want to convey.