While there is some potential for over-reach, and a kind of stereotyping of Chinese academics, this is not without basis. A lot of them have abused their welcome, and done actions against USA - all while funded by US taxpayer. The Chinese govt has many people in its pay, some willing, likely most unwilling and coerced. But a spying operation is an offense.
China is a dictatorship and any Chinese student can be put under pressure with their families at home. That said, the vast majority don't study in foreign countries to spy for the CCP. But obviously with this leverage there is a limit on what you can say in public. Especially since a lot of platforms decided that there have to be consequences for speech. Those demanding it most strongly just tend not to be the brightest stars in the night sky because that in turn has the consequence of vastly empowering repressive tactics so that people take more care of what they say.