I don't know where they got this letter form the Pope, but I wish he would discuss issues in the Church with this sort of candor publicly:
I understand quite well your concern regarding the participation at the Assisi meeting. However, this commemoration would have to have been celebrated in some way and, all things considered, it seemed to me that the best thing would be for me to personally go there being thus able to determine the direction of it all. I will nevertheless do everything in order that a syncretistic or relativistic interpretation of the event will be impossible and so that what will remain is that I will always believe and confess that which I had called to the attention of the Church with [the Declaration] 'Dominus Iesus'.Wouldn't it be great/funny if at Assisi III itself he got up and said, basically, "Yeah, the other two events were real scandals, gave the impression of relativism/indifferentism, and I'm here to basically put an end to that. Make no mistake: Catholicism is the one true Faith. Thanks for coming, though, we're more than willing to cooperate on a humanitarian level in spite of your schisms, heresies, and false gods."