People in China talk about it all the time. But you do have to speak Mandarin or the local dialect to hear it. Many don't want to talk about it in English because it gets annoying to hear expats and tourists preaching to them.
This is a good summary, but it's even more nuanced than that.
For example, while China did lose the Sino-Vietnamese War, they did achieve two important objectives.
First, they proved to be a trustworthy ally to Cambodia. This is why those other SEA countries like Cambodia, Laos, and others that were bullied by Vietnam are much more pro-China right now.
Secondly, they showed that while the USSR was a Vietnamese ally, it would not interfere with China.