I have to agree. There are journeyman partsman, just like any other trade, they go to school and apprentice until they get their journeyman ticket. Mostly at a manufacturer's dealership, Ford, GM, Cat, etc..
Now at Joe blow's parts store, anyone who can push the buttons on a keyboard can get a job as a counter person. They're shown how to access parts by make model and year, they don't have to know what the part does or even look like. Try asking for something as simple as a type X 900 CCA battery, most likely you will be asked what its for, the year and model. It's not the counter person's fault, they just want a job to pay the bills, just like the rest of us.
Now if there was a parts store that hired car guys, gear heads, mechanics, etc., I'd gladly drive the 25 miles to give them my business.