There are things that can not be expressed in words, but which can still be expressed. Some of modern art lives within that gap.

Even traditional art often tries to do more than compress concepts, it tries to express the inexpressible.

Linguistic determinism/relativity (Sapir-Worf, etc) explains some of it. People can FEEL that their thoughts are being constrained by language, but they don't know how to express that and maybe don't even consciously realize that it's their real problem. They just figure out that art makes it feel a little better so they do art.

Yes, modern art is literal trash with no redeemable qualities.