I understand what your saying and respect needs to be given on booth sides of the counter. The customers your talking about are idiots in the true sense of the word...they don't know that they don't know. The most dangerous kind.
Many years ago I when I was 18 years old I was a mechanic at a local GM dealership, the parts department was busy and short staffed, I was waiting on parts so I thought I'd go and help out (common back in the day and it was a small dealership). A customer asked me for points, condenser and rotor for his 1974 Impala, I asked if the points and condenser where one piece or if the condenser was screwed to the plate on the distributor. The customer got upset and told me that when I was finished washing the floors in the shop maybe I could wash his car and he wasn't going to buy parts from a kid that didn't have a clue what he needed. I looked at him, smiled and walked away. Then he asked the parts manager if we had time to install the parts and do a tune up on his car. The parts manager turned to me and asked I if had time for a tune up on a 74 Impala. I smiled at the customer and told the parts Manager that I was waiting for wheel cylinders on the car I was working on and absolutely I had time to tune up the car, I turned to the customer and asked if he'd like his car washed as well.
I believe there needs to be more respect, on booth sides of the counter. If I see a younger person at a parts counter, I don't judge him because of his age. I will however look at the persons willingness to assist a customer to get what the customer wants or needs. How well the person listens, and if he doesn't know the answer, his diligence in doing what he can to get an answer. The person I want is the person who cares enough to learn when he doesn't know and truly has the customer's best interest at heart.