I guess it's a matter of priorities. Some experts will deal a lot with air quality in their field, so they go kinda tunnel vision on that. And others (like firefighters) will be very focused on the fire safety aspect so to them that seems most important.

Personally I usually close all doors for fire safety except for my bedroom door because the air quality improvement is just too large. I can open a window, but it usually blows open further due to the wind. Then it becomes too noisy and cold. So I tend to keep it closed when it's cold outside.