I haven’t found anything that isn’t akin to old wives tales backing this claim up. Got any sources?
“retaining a small amount of humidity whilst also allowing a small amount of ventilation. Some bread boxes don’t allow any ventilation, but these can cause too much moisture retention and allow faster mold growth”
https://www.foodtoimpress.com/bread/how-to-prevent-mold-on-bread/
Bread should be stored in a cool dry place to insure it lasts longest. Breadboxes are the opposite of ideal.
Bread boxes are antiquated tech in a time where bread was meant to be eaten faster and as a method of rodent protection. The same with pie cupboards/safes.
From your own link:
They create an ideal environment for bread since they’re cool, dark, and relatively dry. They act similarly to a plastic bag and trap some moisture, but they also release excess moisture through airflow, so you get the best of both worlds.
It sounds like it’s just bad if you don’t know how to use one.