I don't think sex should be the first thing we associate with any character.
Yet sex is a huge part of what Starfire has always represented. As George Pérez said, her attitude toward sex is part of what differentiated her from the other team members: "And in creating the new Teen Titans, the one thing I enjoyed was the fact that of the three new characters we created, two of them were women. And one of them, Starfire, was definitely created for pure sex. The fact is she's sexy, she enjoys sex, and she makes no bones about it. She attacks Robin in the second issue." And of course she was drawn to look out-of-this-world sexy, in a certain way.
Starfire embodies, I'd say, sex with love and—what can make her disquieting for us in the west—without guilt. Sex doesn't make Kory "cheap" or vulnerable or despicable. The male gaze doesn't bother her. And her capacity to love, emotionally and physically, doesn't impede her capacity to fight.
Granted, all those characteristics add up to a fantasy figure for some young men. But all superheroes are fantasy figures representing different human traits taken to extremes.