That's basically the liberal discourse on violence against white people. You can only kill people when it's on behalf of the legitimate liberal government. All other killing in history was immoral, except for when the Americans did it (and we're just going to avoid talking about the bit where they were convinced to do it because Britain said that they weren't allowed to go genocide any more Indians, it was Canada's turn).

The best possible way to avoid realizing the obvious contradictions of this is to never try to answer the question "when is political violence necessary?"