"The Red Communists of North Vietnam invaded South Vietnam, until they were bombed"
So as you see "Red" in a phrase, you know what you are up against.
Can I suggest you go and study the Vietnam War in a little more detail, especially the pre war history.
Hi Chi Min (as he was later to become) just wanted to have a country free of the imperialism of the French. The US originally supported his cause, but then changed their minds and sided with the French. He was not a die hard "commie" but just wanted freedom for his fellow countrymen, a thing the "north" and "south" both wanted. The US propped up a corrupt puppet government, so you then had the true "reds" team up with Ho's forces to try to overthrow the corrupt regime.
If the US hadn't supported the corrupt regimes, the war may never have happened and the country wouldn't have been so hard line communist.
As for 9/11 again do your history and find out who put the Taliban into power in the first bleeding place.
The US has a good history of meddling in foreign affairs and making the situation far worse for their people.
As much as I dislike Trump, the way he is dealing with Iran is better than others would of done (bomb and invade). Don't get me wrong, it's not a good way, but better than others would have done.