Why are black people looked down upon?

Let me tell you one thing that man's qualities,success or virtues should not be measured by the colour of the skin.what black what white all are equal for god then who on the earth are humans to do racial discrimination?? You asked why black people are looked down but firstly who dares to do so when the most talented and successful artist of all time ,the king of pop-MICHAEL JACKSON was black (before suffering from from vitilgo)the whole world respected and loved him .If anybody says something bad about black people give them this striking example and there are many other as well.By the way i am brown skinned Indian