I do kind of agree here. I used to worry that my day humidity was too high. It is an open enclosure, with vent fans , so air flow is great. Depending on weather, like now it is 40 - 50% outside, so my inside humidity has been running high as well. However do to the maximum ventilation I do not worry. When I compare to actual past weather in Yarim/ibb Yemen They run for periods of 50% + all day at some points, why don't they get infections? I believe it is like you say ventilation is a key to this. I thing is you had proper ventilation you could run very high humidity.
All that said, I do believe periods of "dry out" (30-40%) during the day are benificial.