To be honest, I really would appreciate hotels charging me a cleaning fee, too.
From a controllers point o view it makes sense to add a cleaning fee separately, because the cleaning has to be done after each guest and approximately takes the same time, no matter if a guest stayed one, two or more nights. Changing bed linen, cleaning bathrooms, cleaning surfaces, vacuuming. Everything has to be done.
So, the calculation based on a salary per hour like 10,- € plus additonal social fees of 31,15 % in Germany for about 1 1/2 until 2 hours for cleaning a 25 m² apartment leads to 19,67 € - 26,23 €.
But my apartment at all is 44,- until 49,- € per day. So, not to charge any cleaning fees while offering the apartment for just one or two night would be a loss.
It's clear that the longer a guest stays the more the cleaning costs will be compensated through the daily rate, but based on my realistic knowing about staff costs , I couldn't do so.
If my guests book for just one or two nights, they see for what the are paying. Sure, the average price is higher for one or two nights. But until now my cleaning efforts led to excellent ratings and compliments for this part and the cleaning fees seemed to be accepted.