Always easier to blame the rider.
I did not have it in gear, on the other hand decades of that practice has not proven to be a problem. It blew over on the right side so in/out of gear does not come into play.
Airports have a good chance at high winds, but gusting maximums for a given area often come from the vortexes formed by buildings. These wind speeds can be much greater than open spaces. When the buildings are very close like downtown the wind is blocked somewhat, but on the outskirts of town you get a channeling effect.
There is no mark from the side stand digging into the asphalt, but that would cause a left side fall anyway.