The typical American kitchen doesn't exhaust cooking fumes out of the house - the rangehood (typically part of the microwave) just sucks the fumes up and blows them over the head of the cooker, distributing food particles and steam around the entire house (perfect for mold growth!).
It blew my mind seeing this as an Australian, where externally venting fans are standard.
You're not quite wrong nor quite right.... I've lived in the USA all my life, in perhaps 20 or so different houses or apartments over the years, in half a dozen states through both the northeast and midsouth and in my experience.... both ways are common in the USA, unfortunately. I'm not sure why, but I agree kitchen vent fans that don't actually vent outside are terrible
It blew my mind seeing this as an Australian, where externally venting fans are standard.