And I thought puns were the lowest form of wit. Now I see that I'm not getting enough irony in my diet.
I think they've referred to sarcasm as the lowest form of wit just to make a cute headline. It's clear from the story, and the posts here, that it is not the lowest or rather most easily understood form of humor.
But I always think puns get a bad rap. I think slap stick is probably the simplest form. I remember reading in TV Guide about some family who came here from China or someplace like that, they had no grasp of the language at all at first, and the only TV show they could really enjoy was I Love Lucy, since it was so broad and had so much slap stick in it.