He's not an idiot or anything, but he's pretty ignorant about a lot of topics, particularly science. He's quick on the uptake, but he isn't good at understanding how things fit together

That's fine, it's a fantastic way to do interviews. It's a stand-in for the audience - he says "I'm a dumb guy good at punching, so can you break it down really simple?" People that are sharp don't feel patronized, and people that are actually dumb feel it's much more approachable

The problem is somewhere along the way, Joe started believing people were there for him and not the guest, and he started doing more talking and less listening when he doesn't agree with what's being said (especially since he has some pretty bad takes)