I like to highlight one of LKaven's comments (not because I have something again LKaven, of course, but because I have heard / read that same argument upon extenuation):
There it is.
First there is this concept that there is something out there to be understood. Merely contemplating a piece of art is no longer enough: you have to know the artist's statement, you need to talk to him / her and understand his / her motives, you must be versed on the true meaning of art, and keep informed about the latest and greatest in art; that is what you have to do to understand what you are seeing.
But then... then nothing, you just stay there, staring and feeling absolutely nothing. Sorry, but if it does not make me feel something deep inside, I am not interested. Call me primitive if you want, but art that does not transmit a feeling bores me; no matter what it talks about, and no matter how much meaning the author thinks it has.
And there is also this emperor's new clothes emanating from that argument: if you criticize someone's work, it has to be because you do not understand it (there is no other imaginable reason why you could disagree with the author, of course); thus, unless you want to be called a fool, you must say great things about the most absurd occurrences.
This is what I think; now, feel free to bash me for my rudeness and ignorance: I am young, I will recover.
There are a couple of issues to separate out. In this case, I was making a point about exegesis of existentialist works, and whether they mean what Scrutin takes them to mean. [I claimed he didn't. It's been a couple of weeks since I wrote that, so I would have to take a second look at everything to explain that further.] This is aside from the point of whether or not a correct understanding would affect his aesthetic experience of them.
Speaking to your point, I think there is always a question of whether the experience of an art work will yield aesthetic rewards, and to what extent it is necessary for the viewer/listener to meet the art work (or the artist) halfway in order to achieve satisfaction. One of the beautiful things about art is of course that this question often can't be answered a priori. So the question for the viewer/listener is to make a judgment about how much s/he should invest of herself in the hope of achieving satisfaction. This judgment involves a balancing of considerations involving judgments about what the work promises, and in cases where the work promises eventual satisfaction, whether it is worth the investment to gain it. Making these judgments are fraught with uncertainty, but are also tied up in the direction of "the long journey" that the neophyte (necessarily) undertakes.
As someone who understands modern jazz very well, I can say that knowledge about musical theory, modernist aesthetics, as well as an acquaintance with a certain musical/cultural vocabulary involved in "what the artist is saying" all make a crucial difference in the experience of the music. There is, in many such cases, a sense in which the listener "gets it" or "doesn't get it", and in that way, it can be an all-or-nothing affair. In order to grasp a simple joke, it is necessary to have the relevant background beliefs to render the joke sensible in the first place. Without those beliefs, a joke is vacuous to the listener. It is certainly the case in music that a period of study can transform the listener's experience radically, overwhelmingly, and ultimately deliver enormous satisfaction. But this long journey only seems worthwhile to those who see it's promise from a great distance. And of course, there are some journeys that lead to nowhere.
Add to this that there is often a certain gamesmanship in the art world involving people maneuvering for power, fame, and money. The commonplaces of these games are such claims as "I am avant garde," "I am complex and misunderstood," "you are old" (and by nefarious implication thereby obsolete), "you are envious," or "you don't understand". At its worst, this is a shell game involving semantic sleight of hand played around an empty pursuit. Sometimes, though, the most overlooked artists yield unexpected and satisfying aesthetic experiences when you finally get around to seeing/hearing it.