Keeping in mind that the scandal was known since at least as early as 2007 (according to the link pasted on another comment: https://news.ycombinator.com/item?id=32670518), the IOC should have had plenty of time to investigate, if they wanted to. If I understand correctly, the IOC has not (yet) stripped any of the involved athletes of their medals, nor taken any other disciplinary action against individual athletes or the national team. This suggests that either the competition manipulation rules were not in place (in which case the Chinese team would have been still operating within the rules, strictly speaking), or the IOC didn't mean to really enforce such rules, possibly due to consideration for other interests.
I'll also add that, from the perspective of the Chinese government, athletes in the national team are basically in the service of the country because the country is usually paying for all the training, equipment, etc., and so personal sacrifices are expected. This is something any athlete joining the national team is expected to understand. Put another way, if an athlete does not agree with that, they are not supposed to join the national team to begin with. So in the eyes of some people, Ye simply didn't expect she would actually need to make that sacrifice, and got bitter about it.
