"visual art should be totally comprehensible just by sight, it should not require an explanation" is ultimately an argument in favor of cultural hegemony.
like, you know who this is. you don't need an explanation as to who this is and what he's doing. And why is that?
any image could easily explain itself to a viewer, and any image could require an external explanation; it's entirely dependent on what the viewer's background knowledge is, it's not a property of the image at all - and "what can a person be assumed to know" is inescapably a cultural, political question.
If you want visual art that's totally comprehensible just by sight, then go read a fucking comic book.
Comic books are very contextual; we know that a cloudy-shaped text bubble represents thoughts, and a round text bubble represents spoken words. we know that non-letter symbols in the place of a word represent a character saying a swear the publisher isn't allowed to print. We know what panels are and what order to read them in. We know what a superhero is. we know about genre conventions like themed supervillains, superhero costumes, and secret identities. None of these things are explained by the comic book; they are assumed to be background knowledge the reader already has. 250 years in the future, any or all of these things might need to be explained to a casual viewer by an art historian. Even in the present, someone from a different cultural context might also need an explanation; think about the little "here's what order to read this in" tutorials that were included in english manga volumes when manga was first getting popular in the U.S.; the same image required an explanation in the U.S., but did not require an explanation in Japan. That's my main point with this post: when we ask "does this image need an explanation?" that's not a quality of the image itself, it depends on the viewer.
The question of whether art should explain itself gets employed in the art world in a number of ways; some people will say art should be immediately comprehensible to the viewer as an argument categorically for figurative art and against abstract art. others will say art that is immediately comprehensible is low and commercial compared to more esoteric and conceptual art. Because comprehensibility is contextual, I think all these attempts at hierarchicalizing art based on its comprehensibility are wrong.
TLDR; Yes, I'm defending hard-to-understand art from people who insist that everything should be straightforward, but I'm also defending straightforward art from those who think it's crass and lowbrow; comprehensibility can't have any bearing on an image's artistic value, because, again, it's not a quality of the image itself, it depends on the viewer.
