Catholic art exists to lift up our minds to things of the Lord, to get us closer to a state of mind that is holy. That's why paintings have been so effective over the centuries: they, after actual photographs, are the best at transporting one's mind to imagine holy scenes in history or to ponder and mediate on things which are truly of God. Its why we built the great Cathedrals, why we sponsored and lifted the arts in the middle ages. This image does none of that.
An important thing to consider is that if one were not Catholic, what would they make of it? The answer is the same as to why one could imagine it be so disturbing to Children. What would my own kids, who are familiar with our lady, make of it? Their minds are still forming, and connections are not yet so strong. As time goes on, as people grow away from the faith, the shock of such a work is less evident because their connection to the Faith is immature, like that of children. They may imagine it to be our lady, but what she is standing on, what she holds in her hand and why she's holding it, what that line on the bottom, et al, becomes less clear, and just like other modern art, one is free to impose their own fantasy upon it. Without a Catholic formation their fantasy is less and Catholic. And here we arrive at the crux of the problem.
This is what is wrong with the modern religion and why this art is so appropriate for it. One is free to impose their own fantasy on the modern religion. "I believe that this or that is right, and that's all there is to it. You can't tell me I'm wrong, because I know what I'm looking at." They may be right in their convictions they may be wrong. The Catholic may believe this work to be and image of Our Lady's power over the Evil One, and they may be right. A non-Catholic wholly unfamiliar with the faith is more likely to see this as the Grim Reaper; or someone spear fishing, or a Sheppard navigating some rocks. Someone can be right, and someone can be wrong. With classic art- there's really little room for interpretation, unless one is egregious. All of the same parallels can be made with the modern religion.