They're going to embarrassed a lot then, since the ELCA is the largest "Lutheran" Church in the United States. It's not surprising they're in the news more than the LCMS.
According to the ECLA, they believe in the authority of both the Bible and the Book of Concord: http://www.elca.org/Faith/ELCA-Teaching
Of course, I understand if LCMS members want to make an argument that the ECLA doesn't practice it in reality.
Their belief and authority is different in quality. They do not believe that the Bible in inerrant. Their writings include the careful phrasing "Inspired by God’s Spirit speaking through their authors". So anything in the Bible they don't like was the authors speaking and not God. They use it as a buffet rather than a rule and guide.
How can they claim the Bible has authority when they can throw any parts of it out the window? For example, the ELCA tolerates the belief that Jesus was not born of a virgin. They say that in general, Lutherans believe in the virgin birth. The Bible with that kind of authority is no authority at all. If they do that to the Bible, imagine what they do with the Book of Concord...