This is revenge for the "100 years of shame". China is at war with the West.
The US is subject to endless bashing, scrutiny, paranoia, unfair reporting, you name it. If the US does a thing, it's evil or wrong policy; if Germany, Denmark, Canada or France do the same thing, it's perfectly acceptable (see: immigration or corporate tax rates or trade barriers). That has particularly been true for the last ~40 years, since it became the sole superpower.
Now consider, the US is a liberal Democracy, not dissimilar from Western Europe. How much worse should the scrutiny be for an illiberal Communist dictatorship, that has few human rights?
China scrutiny is going to be dramatically beyond what the US has endured, as they rise to have the largest economy and a comparable military to the US.
I'm Chinese, and I just want to say in my experience this isn't true of Chinese media coverage of the US.
For the most part the US (and other western countries) are covered in positive, admiring terms. "This is how American educate their kids. We should emulate that" "How to make XXX-food the American way" "i was shocked how clean US cities are as" "ten most beautiful US destinations" etc etc.
American media and politicians often use the phrase "the Chinese" (also think: "the Russians"; you don't often hear "the British" "the French"). Chuck Schumer says just the other day something to the effect that we must be united in our "fight against the Chinese". It's hard for a Chinese person to read that kind of language without ... feeling a bit disheartened inside. Say what you will about Chinese media, when there is anything critical about the US the target is never "the Americans".
When you use language like "the Xs" you are speaking in tribal-war terms. Good for selling newspapers maybe. But we all know what tribalism can easily snowball into ...
It was frankly a surprise for me to find out just how much hostility there exists on the other side. I'm not necessarily talking about hostility in the sense of outright lying/fabrication in stories about China. A newspaper can choose to print all the true negative stories about blacks that come its way, and skip half of the true negative stories about whites, and still be able to claim they haven't printed a single false article about blacks. Doesn't mean it's not biased against black people. The hostility often resides at the level of what's implied rather than what's said.
The US helped China re the Empire of Japan and WW2.
The US helped China re the Soviets.
The US was responsible for China gaining access to the WTO, which rapidly transformed their economy.
The US helped China develop by pouring trillions of dollars in capital into their country and trading with them in a mutually beneficial manner.
No other dominant world power in the last ~500 years has ever treated China with that kind of respect. As recently as 1992, the US had an economy 15 times the size of China, and it didn't seek to conquer them or humiliate them.
For a while China refused to prosecute these manufacturers unless they sold to Chinese citizens.
Thus China is DIRECTLY trying to get revenge from the 100 years of shame
First of all, are we talking about manufacturing or trafficking? Because fentanyl is legal medicine, used by hospitals. It isn't illegal to manufacture, use, or export when complying with controlled substance laws. What's there to prosecute?
There were some shady outfits that sold to individuals online and those should have been shut down if it was so easy to establish a link, but usually it goes through many hands long after it exits China. Like guns and "Made in China" goods, it's a supply-chain phenomenon that the source manufacturer happens to be in China. Doesn't mean China controls the whole trade. Obviously if the sale is in China for illicit uses there is a lot more big brother tracking and when found out the draconian drug regime there applies. You're reading non-existent things into sensationalist news stories.
Last year, China went along with the DEA to ban the manufacturing of some synthetic variants in illicit use, so they're helping if anything. They didn't have to even talk to the DEA when it's the DEA's job to crack down on drugs on the home turf where the real problem is.