I do wish people would stop using this phrase.
He has NOT served 'his time'.
He has served a portion of 'his time' and is out on license. He is still effectively serving his sentence, and that comes (or at least, is supposed to) with certain conditions. He is not, as you wish to suggest, free to do exactly as he pleases.
Actually he is, as you state there will be certain conditions to his licence, I would assume not to contact the victim, not to give any press interviews, probably see his probation officer once a week and not to commit any other crimes other than that he will be free to do as he pleases.