The Ethics of AI Art

To understand AI Art, you first have to understand how AI functions, so I'm going to give a VERY simplified version of that: the type of AI we use now is called Deep Learning. It learns in basically the same way we learn; by creating connections between something new they are exposed to, and previous things they already know. It stores all the information it learns in networks of tensors, which you should imagine akin to digital synapses, which are connected to each other with differing degrees of strength. The more two concepts appear together, the stronger the connection between groups of tensors that represent and/or process that concept. This is similar to how the brain works.
When you feed a database with terabytes of image-text pairs (images which have accompanying text which explains what's in them, in detail) into a CompVis AI model (specific type of deep learning AI that focuses on visual data), the model creates a cloud of ideas in its database, not of the images, but of the concepts in the images. That is why even if the final model is only a few Gigabytes in size, it can still recreate (with some degree of error, as a human would) any single piece of art that it learned. So for example, if you feed it the entirety of Leonardo da Vinci's work, along with the works of many other artists, and along with pictures of real life, then it will be able to draw you the Mona Lisa. But it can also draw you the Mona Lisa in another artist's style, or as a photograph. And it can draw you van Gogh's Starry Night in da Vinci's style, or recreate a photograph in da Vinci's style, etc.
The important thing to keep in mind, is that these programs learn the same way as humans do. So if we believe that what they do is wrong, then it is also wrong of humans who do the same. Artists who learn how to achieve certain styles often do so by learning from other artists. Even those who are self-taught study the works of other painters, or study real life. At this point I recommend the video-essay Everything Is A Remix by Kirby Ferguson, which essentially can be boiled down to "If we can see further, it is because we stand on the shoulders of giants". People have a tendency to think that they achieve things alone, when in truth everything we do is achieved in a society that is the product of thousands of years of human advancement (and millions/billions of years of evolution, but that's besides the point).
The artists who are angry that these AI models can recreate their artwork, their styles, most of them are ignorant of the internal workings of the AI models, and believe the AI models have images of their art within. Again, this isn't the case. The few who are well versed enough to understand the inner workings, most of them come to the conclusion that what the AI does is acceptable. A very small minority of those in the know refuse to accept it but none of them are mad at all the humans who are likewise able to do the same. Because then they'd have to be angry at themselves, because they know they, like all artists in the world, learn from those who came before them.
The artists are angry in the same way that the teamsters were angry at car manufacturers when they put their horse-drawn carriages out of business. But that doesn't mean the car manufacturers are doing anything wrong. They simply found a way to do the same thing more efficiently.
The entire point of AI is for it to be better than us, to do the things we do faster, to learn faster, and to be more efficient. We have accomplished that. We have created an AI which learns faster than us, and now that it is showing us what it can do, you are angry? That makes no sense. I'm sorry that many artists will lose their jobs, but that is not necessarily true. This technology is also giving many people new jobs. They are learning how to produce better and better artistic images, some of which are impossible to discern that they have been done by AI. I know artists who have included AI into their workflow, and it has become yet another tool for them to create. Don't fear change, embrace it and use it in your favor.