Airbus Windshear Escape Actions:
In the old days we were taught that when the Airbus types encountered windshear after V1, it was announced by voice alert.
The immediate actions were to select TOGA thrust and follow the SRS pitch command orders using full backstick if necessary.
In this particular case it appears that the backstick input went to zero (instead of full up) allowing a downward velocity vector and ground contact.
Maybe the up to date procedures have changed?