Doesn't make them wrong. The PRC is a fascist dictatorship.
As I recall, the PRC "got involved" in Vietnam too and didn't exit until '68. The US didn't support Al Qaeda, but the group that became the Northern Alliance. While countering the USSR and dealing with the Vietnam War certainly drove the issue with opening trade with Mao's evil empire, it wasn't the only reason. Otherwise, we wouldn't have continued.
Tell that to your masters in Beijing. I suppose we did open up trade with Japan in the 1850s, which resulted in the end of the Shogunate and modernization, but the idea that we taught the Japanese to consider the Chinese and other asians (everyone, really) their inferiors is laughable. We embargoed oil to Japan in large part due to their invasion of China and their designs on their other neighbors. Resulting in the Pacific Theater of WWII.
That and Mao murdered, what, 45 million of his own people and that sick, despicable, government commits genocide TODAY. That puts the PRC on par with Stalin's USSR, Hitler's Germany, and Imperial Japan in the murder Olympics.
So, does your sainted PRC still charge families for the bullet after an execution for speaking "truth to power"? The PRC accusing other nations of "industrial espionage" is precious.
No, China doesn't accuse America of industrial espionage, the EU does. And has been since the end of WWII. As in Echelon and later programs:
https://en.wikipedia.org/wiki/ECHELON#Examples_of_industrial_espionage
And of political espionage, as in the US tapping Angela Merkel's and other European politicians' phones. How insane isn't that? That is what the US / Five eyes war against Huawei is all about, America doesn't want to lose its ability to spy on its "allies" through telecoms networks that they control.
As for Japan, your gunboats certainly opened Japan for trade, but when they traded the **** out of you in the 1980s, you had to resort to the same nasty means as you do now with China, as in denying companies access to your market etc. Japan was neutralized by the Plaza accord in 1985, when you had your dollar depreciated against the yen, causing a price bubble. China isn't going to repeat that mistake, but will have your lunch and eventually crush you.
China wasn't involved in the Vietnam war, but had a short war itself with Vietnam in 1979. China hasn't been at war since, which is more than could be said of America, a country that has known peace for only eight years or so of its entire existence.
Mao certainly had land owners murdered in the beginning of the PRC, but had no intent at all to "murder" people during the great leap forward and other campaigns. Quite the opposite. Murder requires intent, and there was no such intent, just a severely flawed system.
China doesn't commit "genocide", never has and never will, precisely because it is a multicultural state since its earliest stages. Genocides are committed by peoples and nations that think they are superior to others, like European colonialists, or "exceptional" Americans, not by states that are by definition multiethnic.
You will not find a single bone or skull in Xinjiang, and the only thing you and other people do is to render the term "genocide" completely meaningless. It is just one of many nasty campaigns to stain China's reputation with lies, using the usual tools of Congress backed and financed institutions and individuals. Like the Born again lunatic Adrian Zenz, a "researcher" whose mission is to go to "war" with China, and from whom the entire "genocide" debacle stems.
What China is doing in reality is combatting radicalization and its roots, like poverty. Yes, it involves shaping up people with "brain washing" in reeducation camps, because that is the only way you can break radicalized minds. You know this perfectly well, having fought against al-Qaida for so long.
Yes, it involves putting people in labor training, to gain experience and enable them to get a foothold in the labor market, enabling them to support themselves and be part of the community instead of being a problem of marginalization, hatred and radicalism. That becomes "forced labor" in your distorted book, and "cultural genocide" when people are no longer allowed to sit in dire poverty and nurture their hatred in cellar mosques, scheming and plotting against the rest of the population.
It is a social reform, and it is commendable. It has given good results, which is more than can be said of your meaningless campaigns in Afghanistan, Iraq, Yemen and what have you not. What China has done is to lift people from a dreadful existence, while the only method you know is a bullet from a gun.
Worth reading:
https://www.scmp.com/comment/opinion/article/3159871/stop-misusing-genocide-political-purposes