It’s not that government doesn’t have the power to grant rights. It’s assumed by default that if the right wasn’t enumerated here (in the constitution) then it exists by default. None of that bars either the constitution (via amendment) or law (so long as it doesn’t contradict the constitution) from granting or conferring or even restricting/limiting rights (again as long as it doesn’t contradict the constitution). All done via the consent of the governed (ie via elected government). We seem to have forgotten we have the power to “perfect” our laws and governing document.