Not only did he have vitiligo, but he also had lupus. If you don't know what that is, please do some research--it's a pretty awful condition, and it's the reason he never went anywhere without an umbrella toward the end of his life.
Put yourself in his shoes: imagine you are quite literally most famous person in the world; you have cameras in your face ANY time you leave your home, and you have two diseases that seriously impact your physical appearance and health. In a world where people obsess about appearance, vitiligo would have ended his career. Ive always thought the right handed glove made it painfully clear he was covering something. Likely a depigmentation patch now that we know. How would any of you handle it? Everybody who thinks Micheal Jackson was such a 'wacko' has NO IDEA what living his life would have been like, nor do you understand how that would impact a person mentally. Many of us just had acne or bad hair when we were teens/young twenties. It turned many of us into self-conscious, basement dwelling redditors. Imagine if you had to be in the public eye under unbelievable scrutiny at that age, in all your flaws and insecurities. Would you try to hide them? Could you even deal with it? Could you handle those pressures and still go on to become (arguably) the greatest entertainer to ever live?