Good enough is never good enough. Encountering an error distracts the reader from the content you are trying to portray. Whether it be spelling, context, or grammar, what they are likely to remember is the error, not your message. While it is easy to understand why content developers whose native language is not English will be prone to more errors, and perhaps be more forgiving, it doesn't make it any more excusable. The same is true for English cultures writing in other languages.
Cultural differences make professional translation extraordinarily important in business documents.
While slang or regional metaphors may be understood and even humorous within the same culture, when literally translated they may actually be insulting. There is a lot more to translation than merely word by word exchange like many computerized programs do. Clear understanding of ethnic values and traditions can mean the difference between impressing or demeaning your potential client. As far as varying attitudes toward communication, it's purely economic. Those who present professionally will be paid in kind.