How can they accept what is in this sermon? To me it is just as unscriptural. Nevertheless they do accept the teachings of Joseph Smith in the sermon above. That should give you plenty of ammunition, shouldn't it? :-)
Perhaps I'll post the Brigham Young sermon on the Adam God doctrine on another thread soon. I would anticipate that such a thread would not last 20 posts. Look how far this one has gone. It's got to be a record for an LDS discussion.