This is actually a tricky question. First your use of "non equilibrium" is incorrect. Without more information on your MC simulations, especially on the applied biases and simulation process, one cannot state if you are in an out-of-equilibrium (OOE) regime (not state) or not. The way you define it as a state far from the ground state can be a "local" equilibrium in which the system is trapped. This can be, for example, a glassy state obtained from quenching (and yes I know the definition of glass as OOE states is a blurred field). In such a case, the system does not need an external force to be kept far from the ground state (because of the energy barrier it needs a really long time to pass) and it is actually not "out-of-equilibrium" in a thermodynamic sense. It is just a very unlikely state of the equilibrium distribution that would eventually relax using standard techniques (in an infinitely long time, depending on your MC moves).
The referee's definition you give is related to the regime of your whole system. If your system is in a steady-state with a bias or a force which maintains it in such a state, then you are in a truly OOE regime. Removing the bias is supposed to let the system free to go back in an equilibrium state, even a local one (not especially the ground state).
I think you should refer clearly to the source of your unlikely configurations and clarify this point in your manuscript.
Sidenote: As an example, some MC simulations use a so-called "local equilibrium" technique to simulate OOE regimes at the atomic/spin level: https://www.sciencedirect.com/science/article/pii/037843719390463E