A prostitute is a human being, not a work of art. Painting a prostitute is not in any way similar to recreating a piece of art with slightly different style.
The fine art is possibly meaningfully different because of context. So far district courts agree. But the Supreme Court is hearing a case now that’s similar regarding Andy Warhol using a photo of Prince.
The prostitute comparison was about art in general - taking something considered worthless and making sone beautiful from it.