A "new faith" with which to dialogue?

We have a good and healthy dialogue relationship with the Uniting Church here in the Glorious See of Melbourne. But I am not sure whether to put this one ("New faith throws out the Ten Commandments") under the category of "ecumenism" or "interfaith" relations? And might it not rather be a case which calls from "constructive dialogue and open listening" within the Uniting Church itself?

What I do wonder is what St Michael's is actually up to. Why go to all this expense to evangelise with this "new gospel" (which infact is actually rather dated and not all that "new" these days - Bishop Spong has been preaching it for decades)? I mean, I can understand the reason for proclaiming the gospel of the sacrificial death and resurrection of the only begotten incarnate Son of God to all nations - but if all truth is relative, what's the point in preaching this one particular take on "truth" so enthusiastically?