I'm not sure this point is relevant unless you're implying that because the system is imperfect we should introduce more systems in place that can be just as easily imperfect in the same ways.
The point though is that change is useless unless it’s change in a good direction. If something is going to be changed, it should be shown to be better in some way.
No one would claim that the existing system is perfect, but there is a great deal of difference between the assessment of a physician or magistrate and trial by a jury of one's peers. A jury of twelve is standard; I know of no requirement that twelve physicians deem someone a threat to himself or others. Furthermore, there are stronger protections for habeas corpus than there are for people involuntarily committed. Those who are accused are guaranteed a lawyer; those who are committed have no right to an advocate, which is doubly bad considering that they are often drugged in ways that dull their mental faculties.
The great majority of cases don't go to trial. Instead people are threatened with punishments vastly disproportionate to their purported crimes, and thereby intimidated in to pleading guilty irrespective of their guilt. Defendants without the financial/social resources to mount a solid defense don’t want to take their chances when faced with a 20 year prison term or whatever, not to mention a slow process that leaves their life in limbo for months or years even if they do eventually prevail. A NYT story a few years ago claimed 97% of federal cases and 94% of state cases end via plea bargain.
For those who do go to trial, the right to a lawyer is often pretty weak support. Public defenders are grossly underfunded and overworked, and there is no guarantee that they will be competent or committed to the case.
A jury of ones 'peers' is rarely the case either. Yes, they are citizens, but they are rarely of the same background, ethnicity, or social status. They are hand selected by lawyers to remove people that might be sympathetic to your plight.
I've never heard that jurors are the best and brightest among us. Often the highly educated and analytical are removed from jury pool.
