This is vague and non-specific statement. Do you know what Demi said or did that that resulted in his banishment other than the cryptic "he banned himself?"
Careful Dio, you're treading on some thin ice with this one. One must stick with mindless groupthink during times of crisis. Or hadn't you heard?
Kindest regards,
Callahan
Anyway, to paraphrase him would not do his self-bannishment justice and it would be difficult to select any one, or ten, things to mention. He started the process with his first thread shortly after the attacks and continued to work diligently in that direction until he succeeded.