I think that Ecumenism is justified in the belief that the Christian church can offer more to more people if lt lacks so many sects or divisions. When Ecumenism first gained prominence after the Second World War, the reality was that so much destruction, loss of life, and unearthing of human evil had to be seen as the primary threat against Christianity. The need to establish territorial sects could not be seen as more important than the spiritual state of the world at that time.
Ecumenism was justified in a broader context with its teaching of Christ as Redeemer. Edward Schlink argues that political and institutional territoriality are not the driving force behind Ecumenism as much are the teachings and appreciations of Jesus. In Ecumenism, a broad appeal to Christian spirituality is seen. It is seen as more relevant and more meaningful than establishing barriers that could inhibit it.
Through this, the justification of broadening the focus of the religion so that its appeal and understanding are on display rather than what is perceived as institutional differences is offered in Ecumenism.