Actually I think you are in error with your take...try flying on miles with BA vs using those same miles to fly to the same location with one of their partner airlines.
I think you will find the fees are completely different and are, typically, lower.
They do this to mitigate the impact of frequent-flyer mileage.
Last point...any chance you might respond without an insult?
This is the reason why those of us in the back pay $600 in fees on a $900 flight.
Sybaritic luxury paid for by the masses...particularly galling when the majority of those 'up front' are on complimentary tickets...