Because ticketmaster.
They used to charge a pretty high delivery fee for e-tickets. When they were first introduced they where the same price as having an actual ticket delivered. They have since stopped that, but will find a bunch of ways to charge you extra fees.
Some venues add restoration fees, why should i be paying a fee to help you with the up keep of your building? Surely that is the cost of doing business, I don't pay a fee at the supermarket because they want to refurbish.
Other annoying things I have had, is ticketmaster charging £10 each for delivery, on two tickets I ordered. Both where delivered in the same envelope using standard postage, which is less than £1