While most autopilots will disconnect if bashed or tugged, it's not a recommended technique on any aircraft I've come across... and most certainly not on any fbw Airbus since it risks an immediate and unwanted control input. Even if the system had required sustained pressure, what difference would this have made other than delaying the accident by a few seconds?
Why is there so much discussion of the autopilot and it's disconnect system when neither was in the slightest respect at fault in this event? Is it perhaps more comfortable ground for some than discussing the human factors involved?