I don’t know china is a good word or not, but China has its own name in Chinese 中国. And Japanese just incredibly created a new name for China in Chinese character, 支那. Maybe some would say that’s Japanese, not Chinese, and it’s from the English pronounce.
OK, let’s image we call Japanese 泥洪, or call UK yonaited kinden, I am not sure if these examples are correct, but the fact is you never want another country to give a nonsense name to your country, IN YOUR LANGUAGE.
And Chinese don’t like this nonsense name, and if you still blabla that’s just a name created by English pronounce, yes, that’s a affront.