At the end of season 3 of Person of Interest, we see how the new rival AI Samaritan needs access to the government feeds. Greer explicitly asks Senator Garrison for permission to access them in episode S03E20, "Death Benefit".
However, after Season 2, the Machine is independent from the government and still has access to the security feeds. The same thing happens in season 5, when the Machine is built up again. Why can the Machine have free access to the data while Samaritan still needs that data from the government?