>What portion of those arrested + detained are the type of people we want in society/civilization?
Check a list of countries by rate of incarceration[1]. Then ask yourself if it's likely that the US, El Salvador, Turkmenistan, Palau and Rwanda are the grouping that have it right. That's the top 5, in order, all at 511+ per 100k.
For comparison, Australia is 160, England is 130, Canada is 104, France is at 93, etc.
[1] https://en.wikipedia.org/wiki/List_of_countries_by_incarcera...
Edit: Generally, I read all that as "probably 3 or 4 of every 5 US prisoners don't need to be in prison".