Surely booze/drugs are involved....could not imagine someone saying this in front of a crowd stone-cold sober!
Happens all the time. There are whole groups of comics who live to get heckeled...They can annihilate the hecklers pretty quickly...unfortunately Mr. Richards went lowbrow.
The only problem with an exchange like this, is that at some point, you as the comic, have to leave the club...that's when most audience rebuttals take place, on the street.