We didn't have good relations with Vietnam for the decade after we left their country. Yes, we have good relations with them now. It's been 40 years since we stopped dropping bombs there.So when does the statute of limitations begin for hate based on what happened in the past?
We actually have good relations with Vietnam now because their leaders were smart enough to realize that the past shouldn't color the present.
It isn't that the US did one bad thing in the Middle East 70 years ago, we've done a continuing string of bad things there for many decades, both covert and overt. We've still got troops in the area. How many troops from Middle Eastern countries are stationed in the US "to keep the peace and look after their concerns here"? You mess with someone long enough, over years and years, and they'll bring up their children believing that you are unrepentantly evil - that gives you an entire generation to deal with. Eventually everyone there "knows" you're unrepentantly evil. That's going to take a long time to wear off.
I have no love for terrorists - people who kill civilians to spread terror should be dealt with quickly and "with extreme prejudice". But that's a very specific, focused thing, not carte blanche to start making any changes we see fit, to entire governments in the area. We had a lot of sympathy and support from the world in the wake of 9/11, but president Bush p*ssed that all away, capitalizing on American anger towards terrorists that had come from the Middle East, and parlaying some trumped up charges about WMDs (our intelligence community was telling him the rumors were bunk, but that's not what he wanted to hear), into a full-scale takeover of Iraq. But we didn't bring enough forces for a full-scale occupation, because the neocons insisted we'd be welcomed with open arms as liberators. So that degenerated into a huge lengthy deadly mess. And a lot of civilians got killed in the crossfire. And for every one civilian killed, there were a dozen relatives who saw us as the reason for that death, and hated us for it. Doesn't matter that Saddam was a bad man, and was killing some of his own people, by coming from far away into their part of the world and invading a sovereign nation who had not attacked us, we made sure _we_ were the bad guys in the eyes of an awful lot of people there.