I think everyone has a crack in their personality... perhaps he would be overrated if we ignored the bad points about him, however, its not that we have ignored the bad points but celebrated the goodness in him. He did a wonderful thing in America, and that is why we love him. Same as Churchill helped the british through WW2. What he did was amazing, and we celebrate him for it, but he was a womanizer and arrogant. He's not over-rated, simply idolised for his goodness.
Why don't you like Martin Luther King?

When you do something good, would you like it, or think it was right that no-one would praise you because of a fault in your personality?
When i do something good, i get praised for it. The faults in my personality are still there... I'm not being praised too much simply because i have faults. tutut

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"Never let the future disturb you. You will meet it, if you have to, with the
same weapons of reason which today arm you against the present."
- Marcus Aurelius Antoninus