At that time, in Germany there was 'trash art' already, it was unclear between goods (mass product) or artwork? Due to exploring Design through Bauhaus. 'trash art' was against valuable culture. Even today, in Germany, there is 'trash art', which is the important avant-garde. The issue of 'trash art' is just transformative noise that does not solve the social problem, and as an artwork has no value, that is the aim of 'trash art'. However, Duchamp had conceptualised his account of 'ready-made' philosophically, which is not "ZERO degrees".
I call Duchamp's chamber pot is one of the designed goods, and he conceptualised 'entity' in modern society. he showed that design and ethics.
That was not a joke of him, rather, his work ridicules the Art Enlightenment and the Western Enlightenment towards German Nazi Art ironically. Because German Nazi Art was no meaning as 'Art', they believed that they are the world's important artists through German Idealism essentially, actually, they had just copied from the Italian Renaissance for their hegemony. That was the problem with German Idealism, who did not understand German idealism, even today, a very few Germans can understand German idealism, such as Kant essentially. It was the fashion in Germany at that time. For example, Heidegger was a fashionable philosopher, who was not essentialist, he played just as if an essentialist and as if German high cultur.