BA are not always good at the queue management. Last time I was in Nice the line for Club was longer than the other two lines put together, for a 319 that has what, about 24 Club seats?
The old argument about the colour of the card you have will go round and round but it is self defeating if all it means is you don't actually get the priority you paid for for that particular flight. Never mind if you're a gold card flying in eco, get in the eco line!