No? My point is that Vietnam and China have a centuries-long history of antagonism; to take China's support of the North during the Vietnam War as anything other than realpolitik is to miss the greater context.
FWIW, I agree with you regarding the dangers of communist purges- I lived in Laos in the late 70's/early 80's. I saw plenty of first-hand examples of what happens.
Except for the Vietnamese invasion of the Chinese satellite regime in Cambodia, and the literal shooting war between China and Vietnam immediately afterwards.
The Sino-Soviet split was a Very Big Deal, and Vietnam was firmly on the Soviet side of that split.
https://en.wikipedia.org/wiki/Sino-Vietnamese_War
https://en.wikipedia.org/wiki/Cambodian%E2%80%93Vietnamese_W...