Old Kooky Man is Stewart's MO basically since he left the Daily show. He's done some other vids on his cell or guest spots, but it's usually the same sarcastic/meta humor mixed in with some truth and likely genuine viewpoints.
I thought it was funny seeing Stephen trying to do some damage control, just in case some people might think Jon's rant went too far.
But his comedic timing is still on point:
"When you slice an atom this way, you can power the entire world with electricity.
When you slice it that way, you blow everything up.
Guess which one we tried first?"