The goal of the FBI (and the goal that you appear to be advocating here and later in this thread) is to criminalize normal, open scientific exchange between American and Chinese scientists. They hoped that by going after one of the most high-profile ethnically Chinese scientists in the US, they could make an example that would scare everyone else away from normal scientific collaboration with Chinese scientists.
> A naturalized US citizen doing research with federal funding, especially from DoD and DARPA, has no business participating in conversations with PRC officials while using "we" and "our" to refer to China and its ambitions
First of all, anyone can express themselves however they want, and even if we believe what the FBI wrote in the complaint, there's no evidence of espionage or other wrongdoing here.
Second of all, it came out that the FBI had truncated and fundamentally misrepresented this email. This email contains Prof. Chen's notes on a talk he saw by a Chinese scientist. The "we" and "our" in the email are part of Prof. Chen's paraphrase of what the Chinese scientist said.
The US already went through one paranoid period in the 1950s in which it targeted scientists based on their ethnicity and perceived political views. One of the people the US government went after was the co-founder of the Jet Propulsion Laboratory, Qian Xuesen. They stripped him of his security clearance, which effectively ended his scientific career in the US. When he tried to leave the US, they arrested him and held him for years. When he was released, he went to the People's Republic of China and founded their rocketry program. The US' persecution of Qian Xuesen was not only immoral, but stupid. Not much has been learned in the last 70 years, it seems.