Baloney. Too much soap and water in the world to stink. And if they just walked in off the savannah and left their spear at security, there are plenty of restrooms at the airport.
Not baloney. You haven’t noticed how hell-holes tend to be very dirty? (And they tend to be unhealthy and scrawny for lack of good food and water.)
And then it is a habit, because they’re not used to having those amenities. If they get used to the idea, maybe they’ll start using the soap in those restrooms.