Only 1 of the 20 “notable” thallium poisoning incidents listed in the Wikipedia article involved a Chinese person. That 1 of 20 is the same one you linked in your earlier post. The other “notable” cases involved persons from Australia, Cameroon, South Africa, Qatar, East Germany, Ukraine, USA, Iraq, Norway, Russia, Japan, and the UK. Persons from all over the world have poisoned using thallium. There have been dozens of similar news stories about incidents from all of the world in recent years, with many from the US. It’s far from primarily an issue with Chinese persons.