I feed mine chocolate stars all time. What made you think it was hungry? If its not it pass it up. I've had to take them out a few times. Now it's only when I see the shrimp that I'll feed.
Try and move the star closer and see if it grabs it. They like to to hunt. Don't be surprised if its just toying with it. I know it doesn't help the concern with corals.
"When creating an aqua scape, strive for the beauty of imperfection, as its art and there is no wrong or right, it's left open for interpretation" James Findley