Up until the 9/11 conspiracy ranting, I didn't disagree with his opinions. However, presentation matters. Diplomacy matters. In that, he utterly failed.
Given his normal material I don't know how he could present his arguments in any other way. Put another way most conspiracy theorists are not open minded and willing to listen to logical arguments that discredit their point of view and beliefs. They deal with this by attempting to batter their verbal opponents in exactly the same way he did in the interview. By shutting down any honest argument the fantasy is preserved for another day.
The problem here is that he stepped into the real world and does not know how to wear big boy pants and have a normal conversation.