If you are concerned that authoritarian regimes would de-anonymize us and the responder thinks that all authoritarian regimes have already effectively de-anonym

If you are concerned that authoritarian regimes would de-anonymize us and the responder thinks that all authoritarian regimes have already effectively de-anonymized us then... what is there to fear? You could attack their statement that is has already happened or you misstated your concern - possibly by including some entities in the list of authoritarian regimes that the responder doesn't consider to be authoritarian.