The painting is IMHO absolutely pointless. The fact, why it attracts such a huge attention is it's price tag. And because of the attention it has attracted (thanks to it's humongous price tag), for some people it is worth the money. It is also an ego-thing. If you can afford to buy a $3 million pointless painting, you are obviously more than anybody else....more of an a$$hole in my opinion. And you even have the gift of "understanding" art.
To sum it up: It absolutely doesn't matter what the painting is about, the price matters. It's just a whiteman's bling-bling.