How should we be missional?

Helder Camara says this:

"Instead of planning to go to the Third World to try and arouse violence there, stay at home in order to help your rich countries to discover that they too are in need of a cultural revolution which will produce a new hierarchy of values, a new world vision…"

[in Church and Colonialism (London: Sheed & Ward, 1969), p. 111.]

Is this right? Does our country need us more than other countries do?