Why not racial profiling?

Police do it all the time when finding perpetrators. the common profile for a serial killer is a white male, single, lives alone. Would it make since to, in the name of political correctness, interview a equal amount of women and mean and various other races as well, when the vast majority fit my original profile? So why not use racial profiling in Arizona (focus on Mexican nationals) or Arabs in airport screening instead of investigating 80 year old nuns and french girls?