It's HSBC being HSBC, I can't say that I'm surprised. Drug cartels and money laundering are at the core of their brand value.
If I had to guess they are heavily involved with spooks and foreign assets operating in China (and if so, why not use them for non-Chinese intelligence-financial shenanigans?) and a lot of their “illegal” activity is unofficially blessed by foreign intelligence.
The bankers must be made whole -- nothing else matters.