Well, you'll get no flames from me about being a communist, since I am one, but that's neither here nor there. The fact of the matter is that people seem to have a right to rip off other people to get ahead in this world. It's part of the American Dream (tm), right? When you go to Taco Bell and pay 85 cents for a bag of cinnamon twists, it costs Taco Bell 6 cents to make it. If I can get you to trade me an Underground Sea for an Intuition, and then turn around and sell that Underground Sea for 30 dollars to unsuspecting rube, I've engaged in one of the most prevalant acts in American society. Retail.
Love it or hate it, it happens, and being outraged about it won't help. I don't engage in any of these activities most days, and I try to make good trades with people, so that everyone comes out happy, but if someone asks me if I'm okay with him trading me a Darksteel Colossus for my Phyrexian Arena, I doubt I'm a good enough person to tell him "Sorry man, but I'd be ripping you the hell off."