[midoridensha]

At least "Vietnam" is somewhat close to the native spelling. I live in Japan, and the English name is nothing at all like the native name (日本, romanized as "nihon"). But you don't see the Japanese government throwing a fit over this. Furthermore, the name in many other languages is the same or much like "Japan": in German, it's spelled the same, but pronounced "yapan" since there's no (English) J sound. What does the Turkish government have to say about the Japanese name for Turkey ("トルコ", romanized as "toruko")? If the Turkish government insisted they spell it "Türkiye", no one here is going to pay attention because none of those characters are part of the Japanese language, nor is that name even pronounceable using the sounds available.

[supercheetah]

It did make it confusing though. For a long time as a kid, I always wondered why I never heard native Japanese speakers say "Japan" unless they were speaking English. While I couldn't understand it, I could somewhere reasonably sometimes hear words where I've seen it's romanization, but not ever hearing "Japan" was quite baffling for a long time.

[rat9988]

You don't have to feel so strongly about other countries pronunciation. It doesn't matter much. You can still use Turkey and people will understand what you talk about. The problem will only arise in official communications between governments. I believe you aren't part of them anyway.