It doesn't make any sense to wand down an 85-year old from top to bottom at an airport. That person isn't going to hurt anyone. It makes much more sense to wand down the young person that isn't carrying any luggage. This isn't discrimination, it's just being smart about using law enforcement resources.
No, racial profiling does not keep citizens safe and should not be practiced. People of all races commit crimes and there is no evidence to suggest that racial profiling is beneficial. In fact, it can be detrimental to people who are innocent and treated like criminals due to the color of their skin.
Profiling can seem helpful but is not ultimately going to keep people safe. It is human nature to look for patterns, and in many of the world's recent attacks their seems to be similar threads. However, the "bad guys" can adapt as quickly as we can make lists of characteristics to watch for. Profiling is also harmful to all of the innocent people who may meet one simple similar characteristic (which in turn will only build resentment and more violence).
No, racial profiling does not make us safe. It has been found that racial profiling only hurts the cause of safety by galvanizing bad feelings among minority groups toward the authorities that carry out these activities. Intelligence activities should be focused toward imminent threats and not toward whole groups of people.