> Why does NPR call Gugusse "a human clown" ? He is not wearing clown clothes.

Strange of you to criticize NPR for that bit seeing as they didn't come up with that description for Gugusse. From the LoC page for the video:

>> Gugusse the clown appears to control the actions of Pierrot Automate, a child-sized automaton standing on a pedestal. By turning a crank, Gugusse makes him march and wave a stick. As Gugusse turns the crank, the automaton gets bigger until it is the size of a grown man. Suddenly the automaton is controlling his own limbs. He hits Gugusse on the head with his stick. Gugusse pulls the automaton off the pedestal and picks up a large hammer. As Gugusse pounds the automaton on the head, he gets smaller and smaller. At the final stroke of the hammer, he disappears.

So they're using the supplied description of Gugusse. If you have an issue with it, take it up with the Library of Congress.