Fans who really want to see their favorite artist/sports teams get extorted, and the money goes to scalpers instead of the artists and venues which are actually providing value. Scalpers provide no value to society.
That said, scalpers in particular seem to cause a whole lot more harm than good in general. As the above podcast addresses, it's a very difficult problem to solve systemically if you are intentionally undervaluing your goods.
You could argue the “true price” is what the scalpers charge (who will stop drinking water when the prices skyrocket?).
But in reality they squeeze the supply to create artificial scarcity. Any economist knows this is market manipulation.
But how do you square that with scalpers causing the tickets to sell out so quickly? I mean, they're the ones creating their own market. They're not really providing a service if they're the ones creating the annoying need for the service in the first place.
Obviously, yes, if I am mad about scalpers' prices, I have the option to not pay them. I would like to go the event, though.