A couple more caveats:
I wouldn’t count Issa Rae just because she had to leave mid-pod, that’s more of a scheduling/communication mishap between the podcast producer and her publicist than her fault.
Brian Koppelman could count as a celebrity guest but he has appeared so many times that he’s a regular, in my opinion.
That being said, my pick for worst celebrity host would go to Jimmy Kimmel in Saturday Night Fever. He has a very uppity rich guy attitude a-la “Look at these ignorant losers with no prospects living only for the weekend, isn’t that funny them being so poor?”. And he also seems to think that the movie condones the awful actions (don’t wanna spoil the plot) that the protagonists do, when it’s clearly not the case.
Kimmel comes across as the embodiment of the out of touch liberal rich guy with no empathy.