Again, there is no Canadian rule of law or Air Canada directive that state that the CVR and DFDR must be preserved after an incident like this. If there were such directives, to preserve both contents everytime there was a GA, wouldn’t you be grounding the aircraft and perhaps crews at every incident until the CVR and DFDR are read and a report concluded?
I think you are taking things to extremes, where that was never intended. This incident was akin to a very very near armies. This was not a normal GA. It's a damn good thing they made one, but because it was made so late and during hat we believe to be a period of severe doubt, means it was not a normal GA in the accepted sense of the manoeuvre. They were within a whisker of causing 00's of deaths. The root cause of this could very likely go back to the approach briefing, or lack of, and then into possible disquieting utterances during the approach. All useful information into preventing it happening again. This was close to the most major crash and loss of life in an aviation accident in USA ever. It was not 'just an incident'.