Because what really makes more sense, 12 citizens, uneducated in law and its application, getting manipulated by differing levels of millionaire depending on the wealth of the defendant/plaintiff?
That doesn’t make a lot of sense, but that’s not what it says in the Owner’s Manual. That’s just how it works out once in awhile. No one’s suggesting the Justice system in the US is magical and flawless. Besides, there aren’t any news articles about juries who get it right and send a guilty person to prison or release an innocent person.