If some person did some wrong, people tend the blame the whole race or ethnicity associated with it without realizing that they are also part of some race which may have done wrong in the past or maybe in the future. For example if some Muslims tend to terrorize the world with their extremists ideas, people generally tend to blame the religion and its book without reading the contents of it. Same thing happens with colored people or someone in the minority, people generally believe that the whole race is at fault, without realizing that you cannot blame the whole race, religion or ethnicity for the acts of an individual. People don’t blame the acts of a white man on the white race just as the acts of an individual should not be blamed on the whole race. If your car has some problem, you isolate that problem and if it has multiple parts broken, you replace it and don’t throw away the car just because the cars lights or any other small thing is not working or is broken.
Same goes with individuals of a particular race, you should isolate that trouble maker individual and should not blame the entire race for the acts of that individual as they overwhelming majority of people are peace loving and hard working good people, it is only the bad apples that make the entire race suspect in the eyes of the whole society. So we should not blame the whole for the sum of its parts as the parts can be replaced in order to fix the whole.