2. There are no controls at all.
They used non-rich people as controls.
Are you sure about that? From the summary "those who considered themselves in higher classes" where the focus group. Was the control "those who considered themselves in lower classes"? If so, it says nothing about rich and poor people, but only about people's idea of their place in society. All of the groups were self-identified. A valid control would be one in which the researchers, based on empirical data, assign individuals to specific socio-economic groups.