To quote John McEnroe, "You cannot be serious".
Indeed, I can and I am.
I know you are a dealer and that is not the issue in dispute.
I agree with you on both of these points.
However, it seems that all you are saying is that it is OK for this dealer to step in and increase the price for no other purpose than personal gain.
Why does any merchant pay less for something than he plans to sell it for? You are singling out this dealer because he purchased something on the open market and raised the price. Other than this transaction being out in the open, and his having successfully bid against consumers, how is what he's doing any different from what every other merchant does every day?
In this dealer's absence, there would have been a happy seller and a happy buyer.
Unless dealers are second class citizens, he has as much right to not be "absent" as you do.
Also, we do have a happy buyer and a happy seller. One of them is a dealer.
His interaction is nothing but self serving.
Very few people go on Audiogon for altruistic purposes. The purpose of the site is to buy and/or sell toys. How is that not self-serving?
He didn't screw anybody, he didn't cheat anybody out of anything, he perceived greater value in the used amp than anybody else did and acted on it. To him, the value in the amp is what he can sell it for. To others, the value in the amp may be how much listening pleasure it brings them. Both are self-serving, and neither is immoral.