Many such terms are used in the analysis of human and social development in order to identify desirable progress. Essentially it is based on the notion of a container or framework establishing a boundary. Whilst this container observation may appear trivial, its effects on cognitive processes are not. This medical metaphor then evokes and legitimates a surgical response which legitimates the excision of the slum with bulldozers. He pleads for alternative metaphors to counteract this tendency.
Simplistic proposals invite simplistic counter-proposals.
Furthermore the metaphor sets up a mind set that echoes the past tendencies to create fortified walled cities and monasteries to keep unwanted people out and to protect the privileged. From this perspective it also becomes clear why those inside might be reluctant to allow the outsiders in. Fake dialogue can then easily result. This label is a convenient one for those desiring to support them. But the label only works if there is agreement on a single boundary and on the unquestionable value of what is on the inside compared to what is on the outside.