P2P File sharing concerning media such as games, movies, and music constitutes unlawfully replicating and distributing an IP of which you do not have the representation to do so. In other words, you do not have the right to copy and distribute the product(s) at hand whether you purchased it or not. You have no right to put a copy of Starcraft 2 or S.T.A.L.K.E.R you purchased online for people to download anymore then the people who put Halo Reach online for people to download without even an initial purchase.
Copyright infringement would mean selling or in any way making a profit off those illegal reproductions.
Piracy means committing acts of violence and theft agaisnt vessels at sea. Even in international waters.
While the used game industry may be damaging to the video game industry, to what severity or whether it is worse or not for the developers is not truly know to either side. To say one is more damaging then the other is a weak stance since no one will ever know.
I would go one step further and say used games are WORSE than piracy. Because with used games you are extracting money from the games market. A used game buyer has money in their pocket, and has shown a willingness to spend it on a game. A pirate doesn't necessarily have money or if they do is not willing to spend it.
I never buy used games, however i do avidly trade in video games. If it wasn't for the ability to trade in games i wouldn't be able to buy any of the games i own. Starcraft 2, Bioshcok 2, Re5, LBP, Infamous and Darksiders alone i have used trade ins to purchase brand new.
The difference between me and the person who downloads games without ever paying anyone a dime?
I have the right to barter my property to anyone willing to barter. Trading in my used games at EB isn't much different then selling my games on ebay, with fliers around my town, at school as a kid, to my friends.
This is my property once i purchase a copy of a game, and i have the right to relinquish it for cash or credit if the price is right to me.
I have the right to give away my property for free or for a price. (trade ins)
I do not have the right to infinitely reproduce my property at no cost to me and give away to thousands of strangers. (Uploading to P2P)
I have the right to sell or give my friend my copy of Fallout 2.
I do NOT have the right to burn him a copy of said game, whether i charge him for it or not.
I have the right to have a garage sale and put my games or consoles up for sale.
I do not have the right to emulate and release console emulate and games available for download, whether i charge people for it or not.
Game companies might not like the fact trade ins exist. Game companies have the right to be upset and pissed and try to work around and gain money back from trade ins, such as the THQ 10 dollar fee, and Sony and Microsofts subscription fees. Or DLC products, or making straight up digital distribution more attractive/cheaper.
It is there right as publishers and developers. However it is my right to sell my physical property to others. If the day comes where a law is created that specific details selling video games to anyone is a crime i think we have more to worry about then the profit margins of publishers.
Games are not drugs, alcohol, or cigarettes, and as long as i am paying for the physical disk (Which is part of the cost of you $60 game) then i have the right to exchange it anyone willing to trade me.