A couple of things:
* Many podcasts deliberately take a slow, clear tone. That's nice, but a small boost in speed (I like 1.4x) and shaving silences between words makes it sound peppier and more engaging. I have the same thing: when I do voice work I have to be slower and clearer than I would be in my own natural voice, because that's the tone that maximizes the audience, but I myself would prefer to be a bit more lively.
* I tend to listen to podcasts when I'm partially but not fully engaged, like driving or running. Pumping up the energy level helps bring it closer to the level of engagement I want to be at to avoid boredom. (It might well be better for me to learn to disengage, but for that what I really need is to not be listening to podcasts at all -- and I try to go for a run occasionally without it for that reason.)
For me, there's also the fact that there's just a ton of content and I want to listen to it all. Even after pruning shows and episodes I don't like, there's still 20+ hours a week of stuff I'd like to hear. I don't know if other people are as easily bored as me, but I suspect that quite a few people are.
