Earlier quoted context omitted.
The difference is that in drug cases, there is almost always overwhelming proof that someone committed a crime. Nobody has a kilo of cocaine shoved down their waistband and doesn't know about it. In a case like this, maybe it's a "giant crime," or maybe it's just a customs violation. Unless you have proof of the entity's state of mind, it's impossible to tell the difference.
The overwhelming majority of cases never go to trial. Too often the accused can't afford to make bail, can't afford to be stuck in jail for potentially years while they wait for trial, can't afford competent legal counsel, and end up pleading guilty to whatever crime they're accused of whether they're guilty or not. The types of appeals that you mention in your other comment are not representative of the bread and bu…
And plea cases come up on appeal all the time (and in fact are probably the typical criminal appeal). A plea bargain agreement generally precludes appeal of the conviction, but does not preclude appeal of the sentence (because the judge, not the prosecutor, decides the sentence).
I have lots of friends who are public defenders. Almost everyone they work with is guilty (much of the work is hammering out plea deals that ensure that they're convicted of the correct things). Same thing for people who work with Innocence Projects, where filtering out all the requests for aid from guilty people is a big part of the work. If the issue were just not sending large numbers of innocent people to prison we would have fixed it. What makes criminal justice so challenging is the constant fight to protect the rights of the innocent within a system where the overwhelming majority of the accused are not just guilty, but obviously so.