Right to carry, but where?
Colorado is a right to conceal and carry state, but as I understand it, the cinema multiplex exercised its right to not allow weapons inside. So, as often happens, even the legally-armed citizens wouldn't have had their weapons on them because they were following the rules. "When guns are outlawed, only outlaws will have guns" applies perfectly to this situation. Ogre Holmes was operating entirely outside the law in all instances.