Here's what was said in that podcast: "...but I will say, I think there are more cuckoo bananas self-published books about the..." "Cuckoo" and "bananas" are slang for "crazy" here in the US. He's saying that those books are crazy--perhaps that they're illogical or shouldn't be taken seriously or they're just really far-fetched.

I'm pretty sure you misheard. That doesn't make sense.