This is to not discriminate when discrimination would be advisable. People often vainly try to be politically correct, thus instead of recognizing a pattern, they ignore a pattern which can be detrimental to themselves and/or others. By choosing not to discriminate based on evidence for the sake of political correctness, a person paradoxically discriminates against the rest of society, as it causes society's detriment.
Crimes analyst: A recent study has shown male's between the ages of 13-29, wearing hoodies, tracksuit paints and nike pumps with a skin head hair cut and multiple piercings are the most common perpetrators of violent assault and other related crimes during the hours of 7pm-6:30am. It would be advisable if the police made an effort to stamp out such crimes by targeting people who fit such a description, implementing searches on them for knives and other contraband.
Police: We cant assume based on the dress code of a person whether or not they have violent intent or are carrying contraband. It would be discriminatory if we focused on one particular group, instead of balancing our efforts by searching the general public at an equal level.
Crimes analyst: The evidence shows a pattern of behavior associated with such a group, thus it would be best if police efforts were directed in such a fashion. To search old women in wheelchairs just as much as the group so described, would be blatant misdiscrimination, and clearly detrimental to the public as a whole.