The point that many people have made here that you seem to either miss or ignore is that DRUNK TOURISTS asking questions about a very painful part of Argentina's recent history from a perfect stranger might not be appropriate. And obviously from the response you reported from the taxi driver it was not appropriate. Whatever you feel your intentions were, you missed. Do you really believe that drunk tourists asking a perfect stranger such a question would be viewed as sincere?

Not sure why you posted to begin with since you have been provided some excellent replies but yet you continue to justify your actions. And I have a feeling that questions being asked of strangers in any country that has experienced war, genocide, ethnic cleansing etc should be done in a respectful and sober manner, not late at night by drunk tourists.