@Sarah977 obviously you are right.
Airbnb collects service fees on the Cleaning fee as well, and OK, I have no problem with it.
But, the Pet fee should either be a one-time, separately charged fee like the Cleaning fee (nonrefundable if the guest checks-in and then cancel or shorten his stay)..... or.... it should be charged per day, the same as an extra guest fee (partially refunded if the guest shortens his stay).
Of course, the host should be allowed to choose how he wants it to be charged, per stay or per day.
The way it is now it is total nonsense.