somewhat understandable why people have this view of him and his show. he let's his guests go on about what they think. it's usually a 3hr show. this gives people the perception that he believes in whatever they're saying because he doesn't interrupt his guests all the time.
imo Joe is very open minded, an avg Joe (had to) that is willing to hear people out and is fair handed in contrasting opinions. listening to the one with him, hannibal burris, and sam harris shows that he tries to take emotion out of argument and see where each person is coming from. but other times he'll just repeat things what he has heard other guests has said. for instance drugs that clogs up the blood for bicyclists when he had lance armstrong on.
i wouldn't say his show is scientifically dense though. that really depends on the guest. so when you have a person like rhonda on, yea her field is science and it's going to be dense in that subject matter.