If you really believed in that interpretation—that the bill of rights guarantees equal and identical liberties to everyone regardless of citizenship status—then what's the argument that those same rights extend only within the borders of U.S. geography? Why would we not, for example, enforce the second amendment right to bear arms on the benighted people of Australia, who don't have it? If we wanted our actions to be 100% consistent with that interpretation of the language of the constitution, wouldn't that be the outcome?
So, I think the answer to your question is that it's not feasible, practical, or desirable to be 100% consistent, and that the law is mostly cobbled together, full of edge cases, hammered into something that sort of works most of the time, and makes sense if it's dark enough and you squint.
So, I think the answer to your question is that it's not feasible, practical, or desirable to be 100% consistent, and that the law is mostly cobbled together, full of edge cases, hammered into something that sort of works most of the time, and makes sense if it's dark enough and you squint.