Those are great questions to be asking. An artist may intend one thing, and the viewer gets another. That's the nature of art. There is no objective right answer. I always ask myself, why did the artist make the choices they did? What is this painting trying to say by the choices in techniques and composition? Those might be hard questions to answer, depending on how much context you have, but thinking about them anyways is valuable.

Personally, I get what Pollock was going for, but it falls flat for me, whereas Rothko and others made that point more effectively. When I first view a Pollock, for example, I think, what is the subject of this painting? There is no obvious center of focus, and the play between positive and negative space is relatively even. Perhaps the subject is color, or contrast, or randomness, or even art itself. I consider each option. On first glance, I see randomness. I look closer, I see that there is intentionality, but the technique was simple (dripping). The artist is clearly capable of more advanced techniques (the background is evenly applied with precise brush strokes, and perhaps I've seen another painting of his that uses different techniques) but chose something simple instead. Why? Maybe to say art doesn't need skill? Maybe to say that simplicity is beautiful?

There are no right answers, but by asking these questions I develop my critical thinking ability and understanding of art. You might ask these questions and still arrive at the answer, "I hate it, and it's dumb." That's okay. It is still art, and art can mean different things to different people. It just wasn't for you. Pollock isn't for me, but I still gained something by thinking about the meaning and the purpose behind his paintings.

If you are interested in developing a greater appreciation, or at least understanding, of art, study the history. Even a cursory understanding of the social, political, and artistic movements of a time can tell you a lot about why an artist made the choices they did. Impressionism was a movement born out of an era of photorealism and perfect proportion. Pollock's paintings came from an era of established subjects and rigid techniques. Regardless, you don't need to know the history to think about art.