Heresy?

In an ELCA press release regarding the recent meeting of the ELCA's Churchwide Church Council, Presiding Bishop Mark Hanson is described as saying the following:
"+ Hanson identified four challenges for the ELCA: building trust throughout the church, creating awareness by telling the ELCA's "story," raising expectations for what the Holy Spirit is doing, and lowering anxiety about sexuality as the church prepares a social statement on human sexuality for consideration at the 2009 ELCA assembly. "We cannot let that social statement define solely the life and work of this church or our leadership," Hanson told the council. "That's going to take shared leadership. If we become so preoccupied with 2009, we are conveying a message that sexuality defines this church, and (because of) sexuality, this church could potentially be divided. Frankly, that's heresy. That's absolute heresy. The gospel of Jesus Christ defines this church." "I think this (the social statement) is hugely important work for us in these next two years. I'm committed to it, but I will not let it solely define my leadership of this church, because I think that's not responsible," he said."

The gospel of Jesus Christ defines the Church. What is that Gospel, and what does a life lived in that Gospel look like? The latter questions are closer to our points of disagreement. How we answer them, and our source of authority for answering them are crucial to how the sexuality statement is received and acted upon by congregations.
Do you think that congregations that leave the ELCA over issues related to Biblical authority are composed of heretics?
Do statements like this contribute to building trust?