I'd say there's two possible answers :
1) Some of this countries are simply your neighbours, hence, it's just simply normal that some hold prejudice against you, and you probably have some towards them too if you're perfectly honest hahaha ! It's the same all around the world, just ask an Englishman what he'd think of the French, or a Frenchman towards the Germans, and so on and on... And sometimes it's even good to laugh at it, just like a caricature.
2) Plain ignorance. Not that many people might have had the chance to get a real insight at Chinese culture, or even to simply visit China once in there lives. The only things they've ever heard of about China was through medias (books, the net, or in the worst case TV), and this informations are prone to be biased by the authors point of view.
For what goes on in the Western world, which I know quite well since I'm French myself, prejudices against China also goes with the current trend in politics. Simply put, the United States of America suddenly realised since about a decade that China is on the verge of becoming a superpower, and they fear you for that. It is in their vital interest to reduce the positive image people could have about China or Chinese people in any nation they hold a diplomatic card with, and playing on prejudices is one way to do the task. Since Europe (apart Russia, evidently haha !) is nowadays nothing more than an American colony, we sadly reproduce the same schematic.
But don't worry mate, despite this most smart people don't judge a book by the cover, and go check out for themselves 😉