Do you have any evidence to back up that assertion? I have several contrary examples. My mother travelled through much of South/central America as a 60 old, taking buses other means of transport, often she was invited to stay at people's homes. Similarly have a very good friend who as two early 30s women travelled through Iran and had similar experiences.

I want experienced small acts of kindness in many countries and in both rural and metropolitan areas. I do agree that different societies are more or less likely. In my mother's travels, she was met with a lot of distrust in Guatemala (but this was reasonably recent after the end of the dictatorship), similarly my best experiences have been in NZ (just walking around with a map in central Auckland often ended up with someone offering to drive you to where you needed to go).