Why does it annoy them ?
The fact that it is an outrageous imposition to charge you for letting someone out of/into the car might have something to do with it !
Bournemouth, & other airports, might need to get their grasping fingers on every little bit of revenue that they can, but these sort of charges are beyond the pail !
The same does not happen if You drop someone off at the library, hospital, bus station, rail station, football pitch etc.- or, does it ? Why on earth has it been allowed at airports ?