I don’t think it is healthy for a country to beat itself up too much over ignominious aspects of its past. If you do that, its citizens become less patriotic and more cynical, and thus prone to adopting the wackiest of liberal ideas that do great damage to their societies. Like people, societies and nations need a health measure of self-belief and pride to keep them going in a positive way. Just my humble opinion.
What you say is true, and I have no wish to impose self-hatred on anyone (especially considering that America has suffered from a fanatical self-hatred for decades). However, I wish to point out that every Communist regime in history (with the sole exception of America under Obama) has in fact practiced totalitarian patriotism. Outside the United States and Israel, the Left presents itself as super-patriotic and in favor of "true sovereignty" (as opposed to being an alleged patsy for the US). In fact, all through the Cold War Communist propaganda referred to all Communist terrorists as "patriots."
I can assure you that neither Red China nor North Korea are practicing any self-hatred.