They've decided not to go ahead. Here's the official statement:
After careful deliberation, the staff of RavenCon have decided to not host this panel due to the late nature of its proposal and the volatile nature of the subject matter. RavenCon is not the appropriate platform for this subject matter, and we do not wish to provide a platform to any side in this controversy. If, however, panelists feel the need to discuss this matter in further detail, the bar is always open.