And he didn't roll like that at the time. From a narrow view, he could come across as a jerk but in reality, it was way out of his comfort zone (at the time). He grew out of it later, it was right person, wrong time. It wasn't like it was just for this song either, Prince barely allowed his own engineers and bandmates to hear him lay down vocals for his own songs especially when recording very "moving" songs. This choice had nothing to do with Michael or the other artists, he knew the cause was important and still contributed in his own way. People tend to forget that Prince still recorded a song for the album, I'm tired of that same old narrative.