Resistance is when you're nobly standing up to the other side and things get a little out of hand. Domestic terror is when the roles are reversed.

I used voltage as an analogy as it represents potential energy, which is relative. Political stance is a potential energy; action (political or otherwise) is, of course, an actual flow of energy. Resistance (via my analogy) is a potential difference across a load, and can be measured as how much energy is needed versus the action you get (R = V/I); via your analogy, it may be how strong a political action you get for a given delta in political stance.

So far there is no moral dimension to any of this. I think that is correct - the morality of a political stance depends on the member of the polity and the outcome that stance will have for them (which breaks down into perceived and actual outcomes). A functioning political system (the thing that governs political stance and political action) will ensure the balance of actual outcomes benefits the whole of the polity.

The delta between Resistance and Domestic Terror is then a question of whether the actors are party to the political system. (Back to the circuit analogy: domestic terror is the massive bulk capacitor charging off the energy in the circuit but with no defined discharge path in the system - until it hits a charge limit, short-circuits, and discharges.)

The convention for what a volt and ohm is has reached a steady state consensus, so the political debate there is minimal, and multimeters of the world can stand united.

OTOH, your laser distance meter may need you to set it in metric or imperial.