It already is exposed though. Badminton matchfixing news on China can be found by searching. But ultimately speaking Chen is a superior player in terms of achievements compared to He. The problem with matchfixing is most of the time, some crappy person becomes the star of China and then they get exposed when they get overseas.
Unfortunately though it's way harder to bribe anyone who is capable of beating China consistently in badminton. After all if they are that good, they would want to go for full glory and no amount of money would change their minds. Therefore it's a worthless tactic.