"Often" more harmful?  You jest.  There are a handful of corrupt prosecutors, I'll grant you.  But "often"?  What evidence supports "often"?

Regarding what you said about it being "part theory, part myth," it's neither.  There are huge numbers of people incarcerated for murder, attempted murder, and aggravated assaults that could easily have wound up as murders but for the grace of God.  That's a fact.  If you don't incarcerate them, they'll continue to wage war on society. Why do you deny that?