Because China censors very common words and phrases such as "harmonized", "shameless", "lifelong", "river crabbed", "me too". This is because Chinese citizens uses puns and common phrases initially to get around censors.
OpenAI models refuse to translate subtitles because they contain violence, sex, or racism.
That’s just a different flavour of enforced right-think.
Don't forget "Winnie the Pooh"!