They don't send "criminals to Harvard", but they have prisons close (if not more) habitable as a Harvard dorm, very humane treatment of prisoners, extensive educational programs, and so on.
And they have less costs, less crime, and a healthier society doing so.
So snark from a country with the largest prison population (by percentage) in the world, huge associated costs, rampant crime rates, and is so backwards as to still have the death penalty (in the 21st century!), is unwarranted.
It’s a bit of a chicken and egg problem we’ve got. We could just not prosecute many non-violent crimes, like our District Attorney chose to do in San Francisco. But that didn’t pan out well and we now have the highest non-violent crime rate of any major US city.
Nature or nurture? If nurture, then it's at least highly plausible that their prison systems have something to do with it. Recidivism is also much lower.
(I'm sure there's a joke about Harvard educated bankers in there somewhere.)
After the fact, it’s a bit late.
The question is which cycle to you, as a society, want to feed? That is the one that will grow. Reference to the "Nordic" experience shows what a long-term shift in focus looks like.
Perhaps there are mechanics in place that goes a bit deeper?
Are humans born stictly social or anti-social, and will anything accentuate these effects in the life of an individual?
Research is quite clear on this matter I believe, but of course there will always be exceptions.
We should send all criminals to Harvard. We’ll save money, and they’ll become productive members of society.