Having an unencrypted video broadcast on a military drone is just a dumb idea by whoever manufactured it. Encryption would seem to be the most minimal requirement for such an application.
Why it hasn't been fixed since is shocking!
Well, to be more accurate, I believe what you're saying, but I don't believe that it is a valid excuse.
Most of the functionality of these drones could be duplicated with nearly off-the-shelf hardware. (at least off-the-shelf for Boeing/Lockheed/General Dynamics/Raytheon/etc).
Not for the Russians it wasn't! Nor for the French, who will happily sell weapons to whoever wants them (as we Brits learnt in the Falklands War).