The software gave them what they asked for at all times, but what they asked for was dumb. Regrettably to me this boils down to the fact that if you lose your airspeed instruments at altitude, close to your performance ceiling, initiating a 7000fpm zoom climb is about as wrong a response as you can have. Having done that if you then find yourself descending rapidly with the nose high you should recognise the stall for what it is. Its no good blaming the software or the system. If you did the same things in a 737 you'd get the same result.
Edit: if you have dual inputs on the sticks it will tell you, and you can override the opposite stick with the priority button. This accident was not caused by confusing dual inputs but by inappropriate and sustained solo inputs. The computers don't make assumptions, they follow commands. What the THS is doing is largely immaterial so long as the aircraft retains the capacity to deliver the commanded load factor, which it did throughout. Pulling and holding full aft stick in an Airbus is akin to pulling full back stick and holding full aft trim on a Boeing. There is no mystery or confusion about it, it's Airbus FBW 101.