I'll preface this answer by saying that this happens to every single party. There is not a single party not vulnerable to the CCP's influence; every single party is. From my report, I can tell you that we have recorded various incidents of political influence, at the federal, provincial and municipal levels down to the school board level.
When I see that many of your colleagues did not vote in favour of denouncing of the Uighur genocide, I see it as some form of pressure that they have felt. It may be through political donations that they would receive in a campaign period; it may be from volunteers that the United Front activities are able to mobilize.
It also may be just that they have a job lined up after their career as an MP and they don't want to piss off the investor. There is a range of answers to your question, but it is a trend that we have observed, not only in the House of Commons but also in the Senate.