Abstract art usually depends on the theoretical approach of the artist. Some artists are exploring pure color or texture of their media (paint on canvas, glaze on clay, etc, etc). Some are exploring negative space, or other things. If you understand what the artist is thinking, abstract art can make more sense.
As to whether you like it or not, that's really a matter of personal taste. I happen to enjoy pure color, and like to see compositions that are not representational, so I've enjoyed abstract art in the past. Nowadays, I believe art is about living, and that seeing paintings in a museum is like seeing animals in a zoo. They are not in their natural habitat, and out of context, you don't get much from them.
Of course, some artists produce primarily for museums, which, I think, is a mistake. But if you like traipsing through very large buildings with high ceilings and indirect lighting, and having pseudo-intellectual discussions, I suppose there is a role for museums and art in museums. I prefer art in homes and in workplaces.
I think art is decorative and story telling. As decoration, abstract art can be quite good, so long as it fits your color scheme or fits other aesthetic purposes. There are times when you don't want people studying art for its meaning. You want it to be part of the background.
Even abstract art tells a story, although you really have to stretch your imagination to get the story, and often you have to have experience with the construction of such art in order to get the story, because the story is about the creation of the work itself. In other words, it's a metastory, or a story about a story, and as such, it has a rather esoteric plot, which few people can identify with, simply because most of us are not artists.
So anyone can splash color across a canvas. And you don't even have to have a theory to do it (although I bet you do have a theory, even if you are not aware of it). You can call it a mess, or you can call it decoration. But remember, a lot of art is about marketing and reputation and status. If you build a reputation, even if its based on your theoretical thinking, you can make your art work more valuable. Usually you need to be first on the scene in order to get credit for it. Anyone can be a Jackson Pollock imitator, but everyone else will say "that's already been done" and no one will pay much for it.
As you say in your question, art is much a matter of opinion. The real question is whether you like it or not. If you don't like it, can you believe that other people might like it? Can you understand that folks might like it for intellectual or historical reasons as much as for aesthetic or story telling reasons? If so, you might not have a problem with others liking stuff you don't like. But often art belongs to a rarified intellectual environment, and folks who are used to pictures that tell stories, have no idea what story a piece of abstract art is telling, so they just don't get it, and wonder what all the fuss is about.
This is perfectly legitimate. The problem comes when government spends a lot of money on "art" that most of public doesn't get. Or government refuses to pay for art that a lot of people get, but it doesn't fit within the academic understanding of art. The Rocky statue in Philadelphia is a good example of the latter. People love the story, and they wanted the statue at the top of the Art Museum steps. But since the image comes from the movies, and doesn't represent much thought, the academe devalued it, and it was hidden in the trees at the bottom of the steps. It's value depends on your opinion of the movie. It means little without the movie.
Most art museums are about "high" art, which is part of an intellectual tradition. You have to know the history to "appreciate" a lot of this art. It's not about liking it, but about understanding what it has to say. This is a way of separating the educated and upper classes from the rest of the folk. So, when you say you don't like abstract art, for better or for worse, you are, on average, saying that you are an ordinarily educated person, who likely doesn't have much more than a college degree in some practical discipline.
Discussions about art, in the end, I would argue, are discussions about class, and a way for people to separate themselves into a hierarchy. This is what people do, and you can rail about it, but you will never get it to stop. My advice: ignore it if it bothers you. Join in, if you enjoy intellectual discussions and fruitless arguments (they can be quite entertaining). And always stay in touch with what you like, based on your own predilections, no matter what anyone else tells you.
If you want to make money doing art, make sure you have a good understanding of marketing principles, and develop a good, convincing, intellectual-sounding story to justify your art. If you are working with a material or a media or a technique for a while, your facility learned through practice will show. Yet, with some techniques, you hardly need any training to put out something credible. And, as always, luck is involved too. So, have fun!
