Why Was It Funny for Obama's Speechwriter to Grope Senator Clinton?

If you look up Barack Obama's 27-year-old speechwriter, Jon Favreau, on Wikipedia, you'll learn that n December of 2008, "a picture of Favreau performing a suggestive gesture (grabbing a breast) to a cardboard cut-out of Hillary Clinton surfaced on Facebook" and that allegedly Clinton's "spokesman referred to the photo as 'an example of just good-natured fun between former rival camps.'"