Because George Carlin, Mitch Hedburg, John Stewart, Steve Colbert, Arrested Development, XKCD, Penny Arcade, Kurt Vonnegut, Portal, Tina Fey, Richard Pryor, Being John Malcovich, Groundhog Day, Princess Bride, Spaceballs, Ghostbusters, Back to the Future, Blazing Saddles, Simpsons, Marx Brothers, The Three Stooges, Pink Panther, 30 Rock, Curb Your Enthusiasm, Seinfeld, Futurama, SNL, It's Always Sunny in Philadelphia, and Monkey Island...:

eep breath:: are all dumb.
There's a list of excellent American comedies using the next best thing to no effort whatsoever. Name another country with a matching number of excellent comedies.