Also consider a large number of Russian and Chinese spies have been American citizens born in America and who've lived in America their whole lives. Collaboration with a foreign government is not 1-to-1 with what country you're a citizen of.
It's certainly not 1 to 1, but it's hardly farfetched to believe that someone born in China and presumably still a citizen of it (and thus not of the US) is more likely to abscond to China with the proprietary IP of an American company than a random American citizen born in America who's lived there their entire life.