Except really, nobody's ever debating anyone's right to exist. That's absurd.
Consider this: If a mass murderer was captured and imprisoned, he could claim that the justice system opposes his right to exist. The trouble with that is he'd be completely incorrect. The justice system opposes his behavior of murder. No matter how much he believes his very existence is inextricably bound to his behavior of murder, the reality is he murders by choice, and it is that intentional action which the justice system opposes.