No, they ruled official acts have immunity. It doesn't make the actions legal. So the President can say "arrest all people wearing sweater vests as a matter of national security" and he cannot be punished for doing so. A court can rule the action unconstitutional and thus an illegal act. If anyone actually arrests people for wearing sweater vests at that point they can be held criminally liable. Though it likely would only happen once the president left office, or he would have the ability to still pardon them for performing the illegal act. But all those arrested would have their cases dismissed in court because the action they were arrested for, was not infact a valid charge.