It's very much a continuation of Western colonialism and imperialism (hence why there's basically a seamless transition between, say, the British government and interests and those of the CIA, especially in the Middle East as America rose to dominance). This is pretty clear to me, and I don't think it's up for much debate. I am less concerned about where the exact borders are between nations and their atrocities than I am with the interests behind those atrocities. If the geopgraphcical landmass of America formed two new countries within the same region, and the ideologies and power within those regions remained the same, it would not at all make a difference to me, nor would it grant them a clean slate.
The interests behind the CCP's heinous atrocities are fundamentally the same ones underlying the preponderance of those of the British Empire and Pax Americana: the accumulation, preservation and consolidation of wealth and power for the ruling class. Moreover, if you want to group the crimes of states via alignment of national interests, you've just dragged the actions of Stalin and the Soviets into China's tally, which strongly undermines the notion of America being 'worse' or even 'on par'.
I remain unconvinced, because it's impossible to calculate that negative impact of America's actions compared to the more easy-to-calculate crimes and atrocities of China. You have to factor in not just America, but the actions it takes across the globe to sustain that empire, including its actions in the Middle East, the dictatorships it sustains (and their human rights abuses), the actions of Israel, Saudi Arabia. The machinations in South America, the resources it plunders, governments it topples, the economic fallout and poverty that results from that, the wars that are stoked by this imperialism and resource plundering. How can it possibly be calculated?
I literally just said the total adverse impact of each on the world is unclear.
That having been said, it would be extraordinarily difficult and unlikely for the US to supersede China's body count when you consider that, above and beyond Mao's infamous purges, forced marches and massed starvation, the annexation of Tibet and the ongoing de facto genocides of Tibetans and Uighers that cumulatively killed , China sponsored and upheld its own particularly brutal dictatorial regimes in pursuit of its interests such as North Korea, Zimbabwe and Pol Pot's Cambodia among others.
Remember that Mao alone is responsible for the deaths, killings and fatal deprivation of ~40 million people on the low end of accepted estimates, 80 million on the high. The Chinese war and occupation of Tibet is responsible for roughly 1.2 million Tibetan deaths (roughly 1 in 6). Upwards of 1 million Uighurs have been incarcerated in Chinese concentration camps. Meanwhile, the CCP today directly and concretely tyrannizes a population of 1.41 billion in a high tech panopticon, roundly depriving them of freedom of speech, affiliation, association and political thought.
Meanwhile, putting aside existential wars like WW2, the Vietnam War, probably the bloodiest American 'colonial' war, even if we were to unfairly assign total and complete culpability to the US for all civilian and military deaths, would amount to 3.8 million. ~3 million for the Korean War. The Iraq War (including the occupation)? About 300,000 total; 1 million on the high end. Afghanistan War (again, for the full duration/occupation)? ~176,000. Since 1948, about 134,000 Palestinians have been killed, assuming we want to, again, unfairly vest the US with culpability for all of that. Let's even go as far back as the time of the American settlers and say the US killed ~9.7 million Indians during its genocide of the natives.
As you can probably tell, even if we multiplied this grim, and rather overestimated tally several times over, it would fall far short of equaling even a conservative estimate of China's body count nevermind those it oppresses directly, or indirectly (and has similarly killed indirectly) through its existential support of horrid dictatorships like NK.
Despite America's greater global reach and age (vis a vis Communist China), I am pretty confident in saying that China, under the CCP alone, is much worse and it's not particularly close.
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