If the artist creates something that he would want for himself, for his own living space, even if he knew that nobody else would ever get to see it, I'll accept that it's art, even if I can't stand it. If the artist is working on commission, the rule applies to whoever commissioned it. If it's something he would want for himself for his private island hermitage, okay, it's his art. Different people have different tastes, and this is his. And I'm fine with edge cases such as making things such as children's art under the sincere belief that he would have wanted it for himself if he were a child. I'm not trying for a legalistic definition, just a general principle that, to be real art, it has to satisfy the artist's personal esthetic desires in the complete absence of social payoffs such as statement making, money, being the center of attention in order to feel more significant, trying to build a reputation, etc.
If it would be something he would want for himself--a vibrant blue canvas in a color the artist finds mesmerizing, for example--then I consider it art even if he intends to sell it, get attention, build a reputation, etc.
I doubt most modern art could pass this test. I think most of it is just cynical manipulation of the pathetic and pretentious by the narcissistic and manipulative. If the artist wouldn't have any interest in it in the absence of an audience, it's just a product.
Of course, I can't know for sure what the artist's motivations were for a piece, but that doesn't matter. My definition of fraud doesn't require me to be able to spot it.