Store auditioning and then buying on-line from others. How do you feel about it ?

I mean, these guys are looking at making $8,000 for a couple of hours of their time

Hardly. Consider the payroll spent on all the time required to order, stock, and display the gear, the time spent by salespersons standing around waiting for customers, dealing with tire-kicking customers who do not purchase, and helping with post-sale advice, set-up, and consulting.  Not to mention the cost of stock, discounts on items that do not sell, employee training, employee benefits, rent, cleaning, bookkeeping, etc. etc.  I would not want to be in that business.

is it so unreasonable that I ask the store manager not to be an idiot?

Not at all. Capitalism is all about voting with your wallet.  I wouldn't buy from an idiot and in America you don't have to either.   

Store auditioning and then buying on-line from others. How do you feel about it ?

Unethical, shortsighted, and harmful in the long term.

chazro beat me to it!

There is a local high end around here that happens to sell used LP's. 
So after listening to stuff I'll "probably" never be able to afford, I'll grab an LP or two.

Like chazro also, I think it's more for my conscience than their financial support.

If I ever win the lottery tho, that'll be the first place I visit! 

It’s theft. And not the cool kind of theft that comes from desperation and need of basic necessities like food, shelter and clothing. It’s the narcissistic type of theft that comes from a lack of a moral compass.

+1 viridian

OP said:

moral compass" is an outdated concept. It has never been particularly popular, besides, it can be interpreted very differently. .. "moral compass" is directly connected to some authority to which it could be connected.

Sorry, don't I don't buy that.  IMO, we all establish our own moral compass.  If you need an outside authority to establish one, then it's not a moral compass.  I don't need or want anyone to tell me what's moral or ethical.