If I purchase a disc based game, I should have full ownership over it. This means I can do whatever I want with it. I can play it, lend it to a friend, break it, use it as a Frisbee, flush it down the toilet, etc. The same principle is applied on any other goods you purchase, such as a chair. Now if I want to resell said item, I should be able to do it. After all, I'm the owner of it.
The main notion here is that any other goods do not come with a mechanism which blocks resell in order to earn the manufacturer money each time it's passed on a new "customer". Imagine they'd impose some kind of wicked system to prevent people from reselling their furniture just so that the original carpenter can earn extra money out of his creation.
This is sadly the same thing happening with software in general.