Your family was asked to do about 17 minutes of convenient, easy preparatory tidying that most considerate people would do even without being asked (as in a hotel or when visiting a friend).

Yet you benefited from coming into a home that, presumably, had all of its floors vaccuumed, its kitchen and bathroom surfaces sanititized, its linens folded and/or readied, etc. Whether it was the host or a service, somebody followed up behind you and likely spent at least several hours preparing the place for the next guest. And instead of it being bundled into your daily room rate like in a hotel, since it's only being done once per stay, it was applied as a per-stay cleaning fee. That's eminently fair.

There are about a thousand of things to complain loundly about with AirBnB and countless things in life more broadly -- being asked to tidy up a little bit or to pay a per-stay fee to cover cleaning? Not really a compelling one.