Your problem and your logical solution is not what you think it is. This is not a failure of design - it is an operator failure.
All quoted From: RV Dehumidifier: Do You Really Need It?
An RV is prone to humidity as it is exposed to an outdoor environment for longer time periods. The most common factors that affect the humidity inside an RV include temperature changes, washing, and cooking. These things contribute a great deal in the damage of body of an RV, as damp air in the environment settles on its walls and causes serious damage, which ultimately extends to the entire structure.
As an RV is a valuable investment, it demands our daily attention and care. To maintain the moisture level of an RV so that the exterior and interior of your RV remains safe and stable, you need to install a dehumidifier. This is a device that regulates the moisture levels in the environment to keep the chances of mold or mildew, which can settle on wall of an RV and deteriorate its structure, at bay.
You can read the rest of the article yourself, including the use of an hygrometer to monitor humidity levels.
Following taken from my RVIA Air Conditioner training book, plus my edits:
Recreational vehicle air conditioning equipment removes heat from the air inside the vehicle, where heat is not needed. (Doesn't put cold air into the vehicle)
Air flow actually is within the vehicle. Air from inside the vehicle enters the evaporator coil (which has the cold refrigerant that absorbs the heat) and then having had its heat removed the air leaves the evaporator coil going back into the vehicle. The difference between in/out air temperatures is how we measure the efficiency of the air conditioner.
The evaporator gained heat is then taken outside to the condenser coil (via the refrigerant) where the refrigerant now gives off the heat that was absorbed in the evaporator to the outside air.
The process can be reversed during the winter to heat the inside of the vehicle or building, if so designed.
Note: and there is also a lot of Not Great information provided in all of the RV forums, not just this one, from mislead good intentions, assumptions, and lack of technical knowledge, that one must sort out.