The way I see it, traders are there to provide you with a service: to make the buying process an easy and enjoyable experience, for which you pay a premium. Which is fair enough – many people would have no qualms about that.
Except in this case that’s really not what happens. In reality, you have traders masquerading as private buyers/sellers, taking all of the fairly priced S/H products out of the market, thus leaving the average buyer with little option but paying heavy premiums for the benefit of the trader only.
It provides nothing of any worth to anyone but the trader, and is absolutely no different to ticket touting, in my opinion.