I have no problem with people who keep games sealed. Why would I, it doesn't affect my life. When those same people get on their high horse about scalpers though, I do take issue with that, because it's pure hypocrisy.
When you buy a game and don't open it and keep it on a shelf, you're unintentionally depriving another gamer out there of a limited title who would want to open it, play it, and use it for its intended purposes. Hell, one could even make a case that at least with scalpers, the game ultimately ends up in the hands of the people who want them. No one forces a buyer to pay that price, they do so of their own desires and free will.
I see a lot of people get on scalpers for greed, but sealed game collecting could technically be considered a form of gluttony.
I personally don't have a problem with either. If you legally purchase a game, you should be able to do whatever the hell you want with it. Let it sit on a shelf for 20 years, open it and play it, or sell it to make a profit. It should apply universally, not to just some random criteria that was arbitrarily decided to be "morally acceptable" in comparison.
It's a major pet peeve. In discussions about limited collector's editions I see people freak out when they don't get their hands on a copy of something that sells out and the first thing people bring up is "omg scalpers gonna sell their copies on ebay!" and it's like dude, you were gonna buy a game and not even open it that could have gone to someone out there who would open and play it, so you have no room to talk. It's pure jealousy fronted with a holier than thou moral high ground. Do whatever you want with your games, and let people do whatever they want with theirs as long is isn't some insane extreme.