Hi,
Perhaps it does use the squat switch to disable the alarm on the ground? It could do that and still disable it at <60kts in the air for another reason.
Of course it was for another reason
The engineers knew very well that an actual speed below 60 knots was impossible (or almost improbable) .. but it could come from a false indication given by the pitot tube
The engineers knew very well that, pitot tubes were not reliable in some flight areas (giving false information)
And even it is not the reason ...for me .. the failure of the engineers is not in the design of the global Airbus flight control system .. but their failure is that not fixing one of the most important measuring device (pitot tube) who collect very important information for feed their sophisticated system
A reliable speed measuring device will never indicate 60 knots or less .. provided you are not in a certain flight condition (a stall is one )