Tens of thousands of the same people we arrested in Iraq and Afghanistan for their involvement in placing bombs, or firing on our troops, have been set free because the host nations can't contain them. Tough on the troops to see the guy who placed the IED that killed your buddy walking free because he promised he'd be good. Psychologically, it had a collective effect on nearly everyone, and robbed a lot of morale. Might've made some less prone to detain a bad guy.
This'll be tough on the victims and their families, not to mention the LEOs who risked their lives to put them behind bars. Sure it'll be 1,000 near parolees, nonviolent or the "truly rehabilitated," but that's not a reassurance to anybody. Psychological effect on the population they're released into is bound to be one of greater fear and animosity towards the government. I would imagine LEOs would have their faith in the system stretched as well.