“You do realize that the average air temperature at 35,000 feet is -50 degrees, dont you?”
Tens of thousands of aircraft fly at this altitude daily and their pitot tubes don’t freeze. In fact, most commercial passenger aircraft have heated tubes to rule out single point failure including this one.
Air France has given several theories on this crash from a lightning strike to icing in an effort to shift blame.
Operator error and controlled crash into terrain.
Please google and do some research on the freezing problems these pitot tubes had particularly under these type of conditions and then come back and act informed.