Stereotypes. Like Marmite, The Kardashians and people who don't look when they cross the road while playing Pokemon Go: they are stupid, but sadly, they exist.
A few years ago, a Viner named Arthur made a short video about how British people shower (with tea bags, obv), thrust onto the internet.com as a deep, meaningful comment on societal norms and expectations.
Naturally, the rest of the world joined in. Soaping up and adding a stereotype of their own, soon there was a collection from around the world from black dudes eating watermelon to Jewish people counting their money and Asian girls with... tentacles. Oh.