Its a sad state of affairs but the same happens here.
Used to be that in Aldershot (military town South west of London) if you wore anything at all in "Maroon" you were in trouble.
It was the home of the airborne units, the parachute regiment, airborne artillery etc, and they wear maroon berets, and off duty maroon sweatshirts. It was a regular occurrence for fights to start just because someone who was not in an airborne unit or even in the military had the audacity to wear the "airborne" colour !!

I am sure it is something to do with the training as the mentality seems to be the same with which ever nation, but common to that kind of military unit.

Just a reflection but it seems to be an affliction of the "minor" special units so in the UK it would be the Paras etc, cant imagine ANYONE from say the SAS ever worrying if anyone wore a sand beret or a regimental cap badge. Seems that the more elite the unit and the better the training the more intelligence required to be a member and the less they are bothered about such things.

To a lesser extent I have actualy witnessed someone refused entry to a military event because an officer from the guards objected to someone wearing a brigade of guards Tie and he was not "entitled", at the same time an officer of the same rank said here have this and gave the gent a tie from the Royal Signals and said I coulndnt care less, and he was admitted, Go figure ?