Men don't want to advertise that they are asking for anything other than the "normal" cut when they visit the barbershop. It seems to be an unspoken rule, one that the barber knows very well. He knows exactly which celebrity hairstyle each man is quietly asking for and how to cut their hair accordingly.
Most people would tend to think that women are the only ones who are interested in celebrity hairstyles; this couldn't be further from the truth. While most men may not want to admit it, they are just as interested, they are just quieter about it.