Earlier quoted context omitted.
It sounds like some of the students not only threatened to report him to the Chinese authorities, but told him that they had done so, and he has proof who made these threats and claims. They didn’t try to hide it.
If they have a right to do that, is that harassment? I doubt Purdue (up to now) has any policy saying it’s illegal to report someone to authorities for something they did. Even if those authorities are not popular right now and the thing they did is ok at Perdue but not at home. Is it a ‘dick move’ and offend our sensibilities? Sure. But that doesn’t mean it’s any different than if a bunch of folks from the US were a…
Yes. Having the right to say or do something doesn't mean it isn't harassment. But more importantly, the 'students' making these reports/threats are acting as agents of the CCP, projecting the CCP's power into an American university, and should be ejected from the country for that. What they were doing was espionage.