The question is not even forgiveness. Most Vietnamese do not see that there is anything to forgive. America was fighting for at least some of the Vietnamese people and that is understood by almost all of them. America was never seen as wanting to colonize or dominate. War is a natural condition. When it is over you get back to doing business and the Vietnameswe, along with the Koreans, are the natural businessmen of Asia.
Neither the people nor the "Communists" bear any ill will toward the Americans. The government-the bureacurats- are looked upon with disdain by pretty much the whole population. Old VC and NVA vets suggested to me or outright told me that they were on the wrong side in the war or that the war was foolish on their part.When you ask about My lai, they just say that those things happen in war and in their part of the world it is more like how war is done, at least in the past.
As for government reaction to improper talk, in summer 2003 I had political/philosophical discussions with individuals and with one group of 20 or so with no one looking over his shoulder. At one point I commented on it and was told that "one year ago we would not have spoken like this but things change". I did feel that I had been foolish then and was more careful after that, but consider, in any Communist country any group of 3 or more will include at least one who will repeat conversations to the police. I know that was still true in Sai Gon when the neighbors of the fellow whose apartment I was staying in ratted out the foreigner to the bo dois which got me a forceful bribe solicitation and induced me to move upcountry forthwith.
Colonel Bui Tin (NVA) emigrated to Paris due to his disillusionment with the aftermath, mainly the reeducation camps which he thought were vindictive and wrong. He writes about it extensively in his autobiography.
The father of my wife's friend was just released from 16 years in prison, for writing some fairly innocuous tracts about democracy in Vietnam.
http://www.pttndt.org (click on Manifesto, which is in English)
"The blind adherence to Marxist doctrine led to an totalitarian state at the expense of the health and welfare of the people. Communism has now proven to be miserable failure, but there are those in Vietnam who are hypnotized by this archaic ideology. It is not a time for failed system or for ideologues." - Prof. Nguyen Dinh Huy
BTW, they commuted his sentence and released him from jail last week for Tet.