So what, specifically, is everyone so worried about?

She is CEO of Megaspeed , who bought $4.8B of nVidia chips and then sold $2B to the Chinese state illegally. There are crimes here, including:

Individuals and corporations caught illegally exporting restricted hardware (such as Nvidia H100 or Blackwell-series GPUs) are prosecuted under serious federal and international trade statutes:

Export Control Violations: Breaking the Export Control Reform Act (ECRA) and Bureau of Industry and Security (BIS) regulations by shipping restricted high-performance computing tech without a license

Smuggling & Fraud: Charges related to smuggling goods from the United States, wire fraud, and using falsified end-user documentation or shell companies.

Those chips were not legal to sell to China. This would involve collusion between Nvidia and Megaspeed.