Believe it or not, there are a lot of people that just like to have a sealed copy for their collection... a good number of people actually buy 1 to play and 1 to display, which might be stupid to others, but this is how they want to use their money. Also, don't forget that it doesn't someone a cent to troll, so don't be surprised if some of those "I bought 6 to resell later" posts are just ploys to piss people off. CAG use to be a better site that didn't have so many of those people (both trolls and resellers), but this is all really relative to what you think of morally right and wrong.
Like buying this CE to resell later for "$10 extra dollars" is no different than buying cheap games to flip. The end result in exactly the same... Someone who could have wanted the game might have missed out and the other person effectively "screwed" that person over by flipping the game.