The point is that "Japan University" is a mistranslation. The official English name of 日本大学 is Nihon University. A fairly reasonable mistranslation since 日本 is usually rendered as "Japan", e.g. 日本航空 is Japan Airlines.
> The point is that "Japan University" is a mistranslation. The official English name of 日本大学 is Nihon University.
Its an accurate translation; though the existence of an official English name would generally eliminate the need for any translation, as using the existing official English name of the institution would generally be considered more proper than translating at all.
> Only if you view assume that English should be the default language
If an entity defines an official English language name, then when operating in English, it would be more proper to refer to it using the official name in that language than to translate a name from another language to English, no?
You do have a point. One thing I am unsure of is whether we can know who referred to it by the incorrect translation first -- the university, or the public.