if slavery actually became legal in America, would other countries do anything?

And yes there are resources for ex-cons, but not all states are equal in that regard. I admit I am not certain where each state stands in that regard. I can't imagine the "tough on crime" (If you're poor) states having the best resources though.

And remember, it's profitable for prisons if ex-cons fall back into old habits. Thus, it's profitable for these rehabilitation resources to be limited or underfunded.

But brutally punishing criminals gets you more political points than rehabilitating them.