well think about it this way:  usually in joe rogan's rants he expresses many opinions as if they were fact, which lead to misunderstanding from people who just follow what he says..    But, its exactly these people who will hear that joe rogan is playing a part of narration in some documentary, and they will watch it..  But this documentary is not made by joe rogan, which means it will be much more accurate.. so the people who are usually misled by rogan will probably learn much more in depth about it..    So its maybe even a good thing that he does this narration