1. I know that, but American condition is the war. They didn't give China another choice, otherwise, they won't establish diplomatic ties with China. Honestly speaking, China really didn't want to attack Vietnam. It's painful, China help Vietnam for decades ( you must be clear how many food, medicine, weapons China give freely to Vietnam during Independent war and Viet-USA war, right? ), the war ruined all friendship between China-Viet. China was just a tool of America at the time, both China and USA just want to deal with USSR, but we dared not to attack directly against USSR.
2. I understand Vietnam need America due to economic development, I also hope Vietnam's economy can develop faster and faster, people can get better lives. But I really don't like war, damn war, please never happen again. I am sorry again for the 1979 war.