Stubbing my little toe gives me an emotion, is that "art"? lol
I would suggest that art is a method is communication. One philosophical definition that I've often used is that "it is a selective recreation of reality in accordance with what the artist considers to be essential."
When viewed through the lens of how art might be a useful tool for human survival, it allows us, as rational animals, to communicate highly complex topics in a condensed, straight-to-the-point manner. Morality tales and other stories, paintings, statues, theatrical plays ... all serve to communicate something.
To circle back to computer-generated "art", I would say that if the computer-generated artwork has a human programmer who was trying to communicate something through the software and its output, then I could consider it to be "art." It is not the computer producing the art, it is the human being who is programming or otherwise directing the computer through an intent to communicate something. If you leave a computer alone, and using some kind of random entropy it just so happens to produce an image of something because that's what the random generator landed on, then it's not art. There was no intent to communicate.
And in the example of computers visualizing some natural phenomenon (the article mentioned an oscilloscope as an example), then it is no more "art" than the image projected into the eye from a microscope since there is no recreation. It is, in that context, a tool for observing reality as it exists, rather than a medium of communication intended to express an idea.