Because it is bullshit. The current US administration is pushing issues now that it has ignored in the past. Eventhough in the broad view these issues are improving dramatically. Look at China today compared with how it was two or three decades ago and it will show massive improvements on living standard, environment, human rights, protection of minorities, intectual property rights, rule of law etc.
I don't have a feel for what is BS in the usual rhetoric, but I saw something interesting today - among the measures reportedly being contemplated by the administration are the elimination of "waivers" for Chinese companies that are listed on US stock exchanges without meeting US accounting/auditing standards.
Now, there may be nuance or whatever that I'm not aware of, but that actually sounds quite reasonable on the face of it. Why not require Chinese companies to meet US standards to be listed here? Maybe waivers were a type of corruption, even if well intended?
China is 1.4 B people; why wouldn't it have higher co2 emissions than EU and USA?
Anyways. We can chat about particular data points. But if you look at the broad picture over decades; you really have to be willfully blind to deny massive improvements that have happened.