I was planning on going in a different direction in my criticism, but the idea of confessing Other People's Sins kept floating into my mind. I regarded it as a distraction at first. Jaed's comment, quite well-put, highlighted for me that this was in fact the main issue.
It is highly reminiscent of CS Lewis's "The Dangers of National Repentance," written in 1940.* I wonder if that was in the back of jaed's mind while writing. If not, you absolutely have to read the essay, jaed. I cannot find the naked essay, but David Foster over at ChicagoBoyz includes it, along with his own excellent commentary, here. I found additional commentary at an interesting site, Isegoria. The key weakness of the Chicago Declaration is that it is confessing other people's sins. It occurs to me that this goes to the root of the greatest danger from the Religious Left, of which they seem blithely unaware. (The greatest danger from the right I am not presently discussing. There are two, actually.)
*The reader is supposed to immediately think "ooh, during the war, then." This is additionally important because of the reference to "Colonel Blimp," a political cartoon between the wars that portrayed a retired military man who was stupid, uninformed, reactionary, and supported Churchill. A few years later, no one who had found such condescending amusement in the character was laughing anymore. Churchill, and Blimp indirectly, had turned out to be right, and those who had sneered at him had to swallow the knowledge that they had nearly destroyed their country. Not that they did swallow it, of course. They found other people to blame. But they were at least exposed for the others. The most poignant of his portrayals was not drawn by the original cartoonist, for reasons that will become obvious. A cartoon drawn after the fall of Paris shows a British soldier evocative of Blimp shaking his fist to the east from an English shore. It was captioned "Very well, alone."