I hate "booking fees" too: would much rather have a bottom line price to avoid any resentment.
In other cases, where you pay a booking fee and the concert is postponed, you can ask for a refund but you DON'T get the booking fee component back, as they claim it's for administrative charges.
Is there any difference between using credit card, debit card or Electron card? There are surcharges when e.g. booking flights, highest for CC, middle for debit card, nil for Electron cards. Which are currently conducting a "super-campaign" against these extra charges, while the banks are also phasing out Electron cards, removing the no surcharge option for payment. I think there should be a similar protest against booking fees for concerts and festivals.