The nature of the IHR can clearly be seen from the application it used for its 10th. "International Revisionist Conference", which required "Those who have not been an attendee at a previous IHR conference" to provide the names of the conference speakers, if any, "or others you may know will be attending" as personal references. If none of the speakers would vouch for you, you were required to provide "two personal references with daytime phone numbers" to permit background investigation before permitting those wishing to attend to do so.
Has anyone here ever been to a convention of any scientific, medical, historical or academic organization and been required to have someone "vouch" for you before you could attend? Clearly the IHR's interest in "open debate" isn't genuine, given their obvious reluctance to permit it at their own conventions! (get pub/orgs/american/ihr/ihr.applicant)