Thing is Judy it’s the classic scenario which we see all the time on their airlines and the trains. When things go wrong the managers hide, communications are hopeless and the front line staff are left to bear the brunt. BA are as good/bad as other airlines in this respect.
I doubt the staff you encountered had any clue what was going on. They are likely agency staff who didn’t have a scooby whether the plane was to be fixed by 2pm, 4pm, next month or next year. At that level they are just acting to orders. I’m sure they were doing their best in the situation.
You have sympathy from many of us but the minute you take the law into your hands by jamming doors open, pushing into the line etc you lose the moral high ground and just wind everyone else up. Sadly the only option is to do what I did on Weds in Geneva ie line up and wait your turn.
Frustrating that you had paid a lot of money, then again it wasn’t the airline’s fault you had to change your agenda either.