I think it's obvious what the point of the song was, what Jermaine's intentions were, whether he knew of Michael's vitiligo or not is wholly irrelevant. The rest of the song makes his intent crystal clear--and his sentiments are shown beyond the shadow of a single doubt. Jermaine was always jealous of Michael--how humiliating it must be to be the older brother, and still so mediocre, plain, and ugly, to watch from the shadows as your younger brother becomes the center of the universe [as he did during the 80's, and not even today's artists have been able to reproduce that level of fame and, for lack of a better term, 'mania.' Not one--Rihanna, Lady Gaga, Katy Perry, Ke$ha, Usher, Justin Timberlake, not one of them has been chased by a throng of loyal fans for years on end. Michael's fame is simply beyond compare.] In any case, imagine having to be compared to that [none of us do, but you can be certain he does, in his mind, and wonders why it was Michael and not he, whom Destiny picked to be great.] So, a lot of that self-loathing and jealousy reflects itself in these words he penned, down from the darkest parts of his own heart, with no intent in mind other than to scratch greatness and to hurt him even just a little bit--that, at least, still remained within his power.
By that time, Jermaine was more than washed-up. He's never made a successful comeback, because he just doesn't have it in him to do so. There was nothing left to do but to give voice to that shadow he found himself being, and to let the world know what it's like to be forever eclipsed by the greatest star who ever shone.
