I think the point of the OP is to say they actually can't rightfully make it illegal and I would agree. Article six of the Constitution states clear as a bell
By this we see the states are bound by the federal Constitution and where we get the idea that anything not legislated by the federal Constitution can be legislated by the state/city etc. However the Constitution has already legislated the bearing of arms and limited all government at every level and prohibited them from infringing the right to keep and bear arms.
Therefore the ruling quoted as well as the one i've quoted several times affirms the unquestioning right to bear arms whether concealed or openly.
Marbury v. Madison, 5 U.S. (1 Cranch) 137; 2 L. Ed. 60 (1803)
To sum up, no law limiting the bearing of arms has any genuine power and those that enforce such laws are in violation of the Constitution as well as the people who are foolish enough to submit to it are submitting to something that Constitutionally has no force whatsoever. This also goes to show just how low law enforcement as well as the justice system has sunk if it's assumed they have the right to make such rulings and thus makes it foolish to try to fight these rulings through the courts as they do not honor nor respect the Constitution. Therefore it is up to us, the People to enforce the Constitution, insisting and demanding the rights we already have.