With due respect, I think you are wrong,......to expect anymore than what you got,....not saying they are right, but I believe they are the normal.
Any longtime serious dry camper like myself, knows that it takes a lot of time and knowledge and energy to get set up for trouble free dry camping, not to mention the maintenance involved. Again, no disrespect, but my common sense would tell me to NEVER rent an RV for dry camping,....you are leaving yourself wide open for a disaster of a trip. In reality,....I can't even see myself renting an RV for even hookup camping, as those places just don't have a clue about using an RV in the field.