Having read movie message boards a lot as a teenager, there are two popular ideas that I came across often - and I think they contradict each other.
The first idea is that no medium is better than any other medium, even at specific things. All mediums have a wide range of potentialities and you shouldn't be narrow minded about what they can produce. They just need to be used correctly for whatever they're trying to accomplish. So the first claim is that you cannot draw conclusions about which emotions or ideas or moods a specific medium is best at expressing.
The second idea is that many spiritual experiences - such as those occurring during the viewing of a great work of art - cannot be translated into language. Note Korine's explanation that he wants to make films that are difficult to articulate in words, that are more like experiences. I think a lot of movie fans, especially those that reject metaphysical naturalism - which might be the majority of them - would sympathize with Korine's statement and even go beyond it, saying that certain audiovisual experiences simply cannot be translated into words. Words might be able to describe these experiences pretty well, but they are not exact replicas of the original experience. Something very important is lost in the translation.
So the first statement claims that ideas, emotions, and moods cannot be unique to specific mediums, while the second statement holds that ideas, emotions, and moods can be unique to specific mediums.
Now, to me the first idea is obviously wrong - and in fact, I was the OP in the thread I linked to. Maybe it's true that, in theory, almost any medium can express almost any idea but mediums certainly differ in what they can express most easily.
That's why various kinds of official documents are written in text, rather than represented with interpretive dance or cooked into meals. Verbal language has the advantage of possessing clarity. It is the ideal vehicle for communicating precise thoughts. It's the same reason why we use language, whether spoken or written, rather than any other language, for philosophy, science, presidential debates, court trials, etc. I don't see any room for arguing that other mediums could realistically be used just as well for these purposes. Certainly, not in our current society.
I think the second idea is true, as long as we don't believe it too dogmatically. I could easily imagine it used as an argument for the futility of language or logic to describe the external world. I only want to argue that it is in fact true that some mediums are better suited for some things than others are. This becomes even more true when we consider existing social and cultural infrastructure: the channels of production and distribution which support media industries in societies around the world. Even if it is true that interpretive dance can express everything that cinema can, it still wouldn't be true that dance can accomplish as much in a society that is far more cinema-dominated than interpretive dance-dominated.
Artists and other communicators should not feel any obligation toward a particular medium. Instead, they should think about what they're trying to accomplish, what ideas, emotions, and moods need to be expressed in order to accomplish that, and which medium is therefore best suited for that project.