If the policy and attitude to begin with was:
"Felons who have been released with sentences served automatically have their rights restored..."
This wouldn't be necessary to begin with. All that time an energy could be spent stopping crimes in progress, and solving those crimes yet to be solved.
If freed Felons are behaving to begin with - why bother them? If they misbehave again, well that's what the Second Amendment is for - stopping 'em in their tracks like any other criminal.