I live in a semi tropical zone in a house with built in wardrobes, we leave the doors open otherwise we get literal mold growing on even clean clothing ... I think the people who built this house were from a non-tropical area, it's full of things like this
Yeah that does seem odd. Cabinets, closets, and cupboards don't generally require ventilation. What little ventilation they require is provided by the fact that their doors aren't air tight.