It’s also cultural. Some cultures see going to a movie as a community event and so they react to it like a concert. You see similar things even outside of that in cult films. Anyone who wants to sit down and quietly watch rocky horror for example is astonishingly strange
Even though I'd probably also be pretty annoyed if I ever heard someone cheering in a movie, people who think IQ is some real-life INT stat are not as clever as they think they are