Are you saying that Dr. William Henry (Bill) Cosby Jr. could never have given a serious lecture or presentation simply because he was also a comedian?
I am saying that a comedian, when doing comedy, is explicitly staying away from the requirements of veracity that non-fiction works have. He or she can use sarcasm, invent totally fictional stories with real life people in them, or just about anything that a reasonable person would consider artistic freedom.
Whatever you consider a serious message or an attempt at a joke in Bill Cosby's comedies, that is up to you. That is called "artistic freedom". If he ever did any lectures in his capacity as honorary Doctor in Education, he surely was evaluated in that capacity, and the lecture was clearly publicized as such.
On the other hand, you are showing all of us that you are willing to take comedy as a lecture. And you are willing to take anyone who never worked for NASA as a NASA insider. This speaks volumes about your intellectual laziness.