If users who should have access (e.g. US taxpayers) are blocked, there is an availability loss. Blocking Tor reducesavailability. Which by definition undermines security.
This is a gross misunderstanding of that CIA triad. You do have access, just not through tor. Nor through Bluetooth. Nor plaintext. “Availability” does not mean you will support every known protocol so that purists and idealists can be happy.