Isn't giving over airtime on your own show somewhat an endorsement? If you're giving them free advertising, you should probably at least spend some time vetting their credibility. Seems irresponsible to give a platform to moon landing truthers.
Well every major and minor news source in the US gave air time to a climate change denier, birther, and vaccination sceptic. I mean in the grand scheme of things, the JRE is nothing and IMO some of these guests put forth great ideas I would have never considered. Speaking to this article, I'd be interested to hear if any research has explicitly set out to verify the "long telomeres cause cancer" claim.
Moon landing truthers get pretty much almost no time with anyone of consequence, so they are already well black listed. Rogan at least lets you see what is inside of the minds of these people, which is fascinating in itself. No subject, no matter how distasteful or apparently false, should be completely eradicated from the human dialog, even if only to reconfirm your distaste for it.
I kinda have a soft spot for ol' Joe Rogan and I see him hosting moon landing theorists on his show as not unlike Louis Theroux doing a show about UFO nuts. Interestingly enough Rogan did have Theroux on his show once, I was hoping it would be a good interview but it went really badly.