Perhaps the ticket agency detailing a transaction charge is a more up front and honest way of dealing with things.

at the end of the day, the ticket agency is a commercial operation, set up to make a profit, and therefore has to make charges. Event organisers will use ticket agencies for their events because it is a simple and effective way to provide an online box office facility.

Many theatres will build their box office costs into the ticket price, so the promotor, knowing that will add that cost into the quoted price, so the end consumer is still effectively paying for that service.