It is certainly a last resort option, but on the face of existential threat, denying Russia a major source of income to finance the war is a legitimate goal.

The major point of Nord Stream 2 was to remove this PoF.

That's the wrong perspective. You have to remember that even at the height of the cold war, the Soviet Union was still providing gas to Europe. This has always been the arrangement. Ukraine stopping gas is not denying Russia income. It's denying Europe a critical resource.