The reseller isn't robbed if he's making more than what he payed for it.

Nonsense.

If the reseller is pressured into selling it for less than it is worth, then he is being robbed.

How much is it worth? It is worth however much a willing buyer will pay for it. It has nothing whatsoever to do with how much the seller paid for it in the first place. It is entirely a matter of supply and demand. Why not tell a stamp collector he is profiteering by selling a rare cover for $2500 when the post office sold it originally for six cents?

tanstaafl.