What is "Art" has varied over the centuries. Some was meant as lessons, or political statements, or rebellion or religious teachings. Others were just very good renditions of individuals, painted for money, and not necessarily intended as anything other than that. Some were just observational, documentary. So art is many things, to many different people, and maybe today in most cases it's meant as "entertainment" or personal expression. So art changes, mutates, means different things to different people.
There is one particular painting that divides my wife (artist, art teacher, art historian) and me (engineer). It was I think by Lucien Freud and we saw it hanging in the Tate many years ago. I can't find an image mow. I recall it was large, mainly green background, and showed a man sitting on a park bench. His head was surrounded by a swirl of black lines. I loved it instantly. She disliked it intensely. She is bipolar, and the emotion it evoked troubled her, whereas I connected with it, still do. What the intention of the artist was I have no idea. I guess that's Art.