[kelnos]

Quite the opposite. The bar for depriving someone of their freedom through force of law should be very high. Sure, the ideal is that all actual criminals are convicted, and all innocent people are acquitted (or aren't even charged in the first place). But until we have a magical system that can achieve perfection, I would much rather the occasional criminal goes free than an innocent person has their life ruined.

If the prosecution fails to make their case, either through incompetence, or simply being outwitted by the defense, that's life. That's how the system as a whole should function. That is rule of law.