You obviously have a right to define personally any word you want, but if not art, what do you call intellectual and technical excercises like this and minimalist paintings?
I'd call them painting, photographing, sculpting, etc. If I go see the Egyptian pyramids and take a picture of myself standing in front of them for my scrapbook, that's not art. If I'm so overwhelmed by the site of them that I spend time finding the best angle, the best lighting, maybe I wait for sunset to have the various colors displayed across the background, etc. because I want to communicate the sense of awe I felt, that's art.
Art schools, museums, art critics and the whole of the establishment has considered this stuff art for almost exactly 100 years now. I'll agree with you, that it creates a bit of confusion that different kinds of art have such drastically different goals and expects drastically different things from an audience, but in terms of pragmatic use of the term, the border between them is pretty flexible. Each approach has more in common with the others, than it has with disciplines outside of the arts.
If someone paints portraits of people, coldly trying to make them look as realistic as possible just for the sake of saying, "here is a picture of person X," I would say that has more in common with a person who just snaps wedding pictures for the purpose of just documenting the wedding. If a minimalist paints a canvas a solid color without a true message that can be expressed through the painting, then I'd say he has more in common with a house painter.
If you rule them out from the category of art, you make it that much harder to communicate with or learn from museums, or any part of the art establishment.
Again, maybe I'm a Philistine, but I don't feel like I've had this problem. If anything, this attitude of mine helps expedite my trips to museums so I don't waste too much time reading tea leaves by desperately trying to read some kind of meaning into the paintings I look at.
If the art world were to adopt your use of the term, it could only make things more difficult. Say I want to study color to paint pure color paintings and my friend wants to paint bowls of fruit that symbolize the decay of society. Do we need to go to two different schools? Should different institutions be concerned with showing our work? Why?
Well your friend would need to decide if he could really communicate a message about the decay of society by just painting a bowl of fruit. You don't need to go to two different schools though, the basic skills can be the same. The difference is how you use those skills, how you arrange the principles you've learned on a canvas and how you communicate with the viewer.
I understand your objection, how can galleries and museums delineate between real, worthy art and simple copying methods or empty chaos-opn-canvas? A valid point, but art galleries and museums all ready do this. They don't hang just anything up. I'm only suggesting that they don't pay lip service and call something art which is clearly empty and rather pointless. I'm not saying they shouldn't hang it up somewhere, certainly the Dru Blair painting (if it's really a painting) might be worth hanging up just to demonstrate his skill, but I would suggest it be hung up only under that label and not as art.
Just my opinions, as always...