Why isn't the Vietnam War called e.g. 抗美战争 ("Resistance War Against America") like in Vietnamese? The Vietnam War is considered by some (most?) Vietnamese people as a fight against US-led invasion of Vietnam.  Hence...


  The Vietnam War (Vietnamese: Chiến tranh Việt Nam), also known ... in Vietnam as the Resistance War Against America (Vietnamese: Kháng chiến chống Mỹ) or simply the American War ...


In contrast, the USA were trying to inhibit the spread of communism, i.e., it was an anti-communism war.  So communist China entered to support the North Vietnamese.

In Chinese the Vietnam War is called 越南战争 (literally Vietnam [越南] War [战争], the same as in English).  I find this historically and etymologically curious: there is the phrase 抗日战争 ("Resistance War Against the Japanese") which could be easily adapted to 抗美战争, but wasn't.

Question: Why isn't the Vietnam War called e.g. 抗美战争 ("Resistance War Against America") like in Vietnamese?
Here I come!

The formal name of 抗日战争 is War of Resistance against Japanese Aggression, that involved Chinese themselves, so we(Chinese) have to resist(抗) them(日).

However we are not imediatelly involved in 越南战争, which is an affair of another country, so we would not to use 抗美战争 which literally seems like who resist American are Chinese rather than Vietnamese, because, I conjecture, generally if we see a noun which lacks a subject, we may suggest the missing subject is ourselves.