The air usually seems pretty fresh and healthy when camping.

What about the carpets?

I’m not sure I follow the implication here, but: my point was that “camping” is generated seen as a fairly healthy vacationing option, so it seems weird to use it as the lower-bound on a spectrum that contains moldy Airbnbs and hotels.

Well, there's a reason people build homes and apartments to live in, and a reason that societies with homes and apartments are healthier than societies that sleep in tents and shacks. Dirt is... dirty.

And yes, the point being advanced in the thread is that compared to camping - which is generally healthy and not something to freak out about! - homes are going to be cleaner, occasional mold issues aside. So it's silly to freak out over the infinitesimally-slight chances of little Timmy and Sally getting dust-mold-smoke cancer-AIDS from a less-than-perfectly-sterile room.

People build houses to protect ourselves and our stuff from the elements (and other climate control reasons), for privacy, for security, that sort of stuff. They are necessary for high-density living (plumbing helps to keep poop away).

Generally though, I would expect camping to be healthier than a hotel room. Hotel rooms and airbnbs are places that many humans go through, and humans are generally the main carriers of human pathogens. The only germs on your camping gear are your own ones.

There tend to be a lot of dust. Less hygiene then in hotel.

Sure. I've camped at a festival with a 1 yr old. Even stayed in a campervan at a festival when they were 6 weeks old. I'm just explaining why parents might prefer the safety of well-known chain hotels vs whatever "fun" darkwater was referring to.