I don’t doubt there’s been some interference by the Chinese government. I’m just not sure they could run a full-on scare tactics campaign without it blowing up.
Everyone I know - including Chinese - got it fairly easily. Many even during their postdoc years.
I believe there is a separate queue if you're getting it via academia and there's no special backlog there for Chinese.
The waiting time for E2 preference for Chinese nationals is 4 years (priority date 9 July 2019, for Indian nationals it's 12 years (priority date 1 Jan 2011). That's what most academics would fall under (I certainly did). Those who fall under E1 preference will get their Green Card a little faster.
US immigration is a fraught topic. People with no or second-hand experience of the immigration system will manage to upset those who had to navigate it even with the best of intents. They would do well to keep silence.
I’ll leave the reasons for that to the imagination
From what I've read, if China wants you (not just Chinese, but also foreigners) you can go from struggling to secure grants to having money thrown at you in China.