To me there are three perspectives that exist when viewing art, the artists intent, the viewer’s interpretation, and the “objective” analysis of the piece. I must object to the idea that the painting lacks meaning because it was displayed upside down and no one noticed, you may look at the piece and find that it doesn’t invoke anything inside you but the people who view it and see something valuable in its expression are not in any way pretending. The artist had an intent and I guarantee you felt that it was a meaningful artistic expression, and yes the “objective” reality is that it is a bunch of parallel lines on a plain background and your feeling that it is “empty” is 100% valid and you are free to voice your opinion. Art is in everything and meaning is everywhere, you listed a rock or chewed up gum as being meaningless but there is infinite meaning that can be drawn from those things if you are willing to open your mind and be a little creative, rocks can be incredibly beautiful, even the ones you see in the cracks on the street, they can tell a story of time if you contemplate where they come from or what they’ve been through, this context doesn’t need to objectively exist to provide a valuable experience to the observer in the same way that a bunch of parallel lines on a canvas needs no objective features to tell a story. You don’t need permission to see meaning in things. Moreover art galleries are places designed to put you into the receptive mode of appreciation, many things that would not be considered art in another context can suddenly seem worthy of attention and deeper thought, hence you mistakenly looking at the dehumidifier, if you were to have some sort of satisfying experience or novel thought while looking at the dehumidifier that is in a way “art”. The metaphor of a language is poor because it implies there is an objective “meaning” to the piece. When it comes to abstract art an artist can tell you what they were thinking about when they created it, what emotions they wished to invoke, or what they see in it but once they release the image from their mind and set it free in the world it is no longer in their hands and you’re free to see it how you wish, this includes upside down.

As for your last statement about being open to being shown a non-bs meaning to an abstract piece, I’d like to know what kind of answer you’re expecting because I feel like you would be unsatisfied by any explanation due to the subjective nature of abstract art. Do you find yourself lacking meaning in other areas of life? Why do we exist, what is the meaning of life, is there a purpose to anything, these are questions that only you can answer and anyone who claims to have the answers are giving you “bs” because it couldn’t possibly apply to your unique life, same goes with meaning in art, only you can assess meaning for yourself, and if we look to objectivity we find that the answer is no, no there is no meaning to life, no there is no meaning in art. though there are many things that you can learn to better help yourself find meaning in art and life in general, and I’d love to discuss techniques for mindfulness if you’re interested.

Closing off id just like to say that it’s ok to not like a piece of art, hell there are tons of art that I find pretty empty myself, but to look at others and judge them for finding value in what you see as valueless is a sad way to engage with a medium designed to be open to interpretation. Art is about creativity, so let’s leave objectivity at the door and make up stories about colors and shapes without worrying about the “truth”