On the other hand, the article talks about their use of composting toilets, recycling water, etc. So they may well not be engaging in the same high levels of water consumption as typical modern families in developed countries.
So I remain unconvinced that a warmer environment automatically and without exception translates to high humidity and mold. (I will confess to being born and raised in the state of Georgia. So my idea of hot and humid is perhaps more extreme than average.)
Edit: If you've never lived in dramatically different living arrangements, you may not realize how much lifestyle choices impact details like heat and humidity.
While getting divorced, my sons and I spent a year sharing a single bedroom at a relative's home. We eventually found that removing all cardboard from all food products not only dropped the temperature by 5 degrees Fahrenheit, it put a stop to roaches being attracted to our room.
Prior to that discovery, our room was frequently too hot and humid. Afterwards, it was vastly more comfortable.
We were shocked by the difference. We initially wondered if we were imagining things, but the room had a thermometer in the window. It consistently made a 5 degree difference.