You're probably unaware that the GP specifically used 'HSBC' because they were caught laundering trillions of dollars of drug money and nobody was indicted.
He probably isn't unaware of that. He may well have actually read the indictment itself or a detailed summary of it, which made clear that the US case was very weak to the point of hardly working at all. In particular, not only did they fail to clearly establish that drug money was really moving (their case was "there is so much cash, some of it must be from cartels") but in particular they failed to show intent by HSBC execs to help drug cartels. Actually their case boiled down to HSBC didn't try hard enough, they weren't suspicious enough, etc. (I'm ignoring the Iranian transactions here which gets into issues of international jurisdiction, as you only brought up drugs).
The reason you think the are guilty is twofold. Firstly US anti money laundering laws are unbelievably extreme. The PATRIOT Act removed the need to have intent to be found guilty of money laundering. Bankers can now be found guilty of AML violations even if they genuinely tried hard and had no intent to break the law. Hence the accusations from the DoJ that were of the form "HSBC should have designated Mexico as high risk", etc. Secondly as part of the plea agreement HSBC had to act guilty and accept whatever the DoJ said about them. So you only heard one side of the story, the prosecutions side (except there was no court case). No surprises that you think the whole thing is cut and dried.
It's no crime to be ignorant of such things, but just try not to hold any policy positions on the subject.
Given that there was never any court case and HSBC was never able to defend themselves, pretty much everyone is ignorant in this case because we never heard the full story. But I'm pretty sure if DoJ had emails from HSBC execs that looked like the ones from BitInstant there would indeed have been prosecutions.