How exactly does providing the latter do anything but piss off surviving conservatives and hardliners and reactionaries even more?
If you want lasting change, the new regime either needs widespread support from its subjects (Why wasn't it in charge to begin with, then, why did it need to be installed by an occupier..?), or you need to scorched-earth, mass-graves liquidate every single participant in the old regime, and all of their supporters (And not just fire them from their jobs, as we did in Iraq. All the ex-Baathists went on to gainful employment in the various insurgent groups, instead.)
Not doing it is exactly why Reconstruction failed. The slavers lost the war, but won the peace, and their politics reasserted as soon as they were allowed to govern themselves.