It’s not some minor quirk of the system. It’s the only reason we have juries at all. If you just wanted a group of 12 people to decide guilt and innocence based on the facts of the case and the letter of the law, you would never hire 12 random untrained nobodies for that purpose. If that is all juries were for, you would have professional juries; being a juror would be a career that required a law degree.

We have juries to protect against corrupt laws. That is the only saving grace of having guilt and innocence be decided by 12 random untrained nobodies. Legislatures can become corrupted and end up criminalizing things that the vast majority of the population does not consider to be wrong. A jury of your peers is the last line of defense against corrupt laws. And this mechanism is the only reason we have juries like we do.