I suppose there are two types of resellers, one that many are ok with and those that deserve to die in a fire.
Good Reseller - Goes out looking for deals, mostly older stuff to buy cheap and flip for money, most times to fund their own collection or help pay bills, it's not their fault they know what to look for and take advantage of this. They went out of their way to do it, their reward
Bad Reseller - Those that find loopholes in pricing systems, find something on sale, or even the new popular thing to buy up preorders and sell them for 3x as much. Those that go to a store and buy up every copy of something they have and resell for more. This happens more with new products than used. The loophole is fine, but leave nothing for those who want in on the deal, maybe for their collection etc. See "El Hoardo" on cheapassgamer for example Not everyone has expendable income like that to even compete.
Now sure, you could argue they are both the same thing but in reality its two different types of product they look for. Good reseller may find something for cheap but sells it for going price, bad reseller gets something so no one else can and inflates the price. However at the end of it all, its the way the world works