It artificially inflates ticket prices by inserting a completely unnecessary middle-man in the purchase process. This is done by people with no intent to actually use the tickets they bought, so it's very much not the same as "oh I can't go would you like to buy my ticket?"
This is similar to a dark pattern I've seen at shopping malls where they offer a valet service, but also rope off all the close parking spaces for valet. This creates an artificial scarcity of close parking spaces which helps to drive the valet business. If they never did this there would be little desire for the valet service.