These guys are only doing what there told to do, some do it more diligently than others and some are just downright rude and arrogant. Its the government, airport authority and the security companies that tell them what to do and expect us to put up with it.
The main instigator for all this nonesense in the U.K. is the DfT, Department for Transport and until they are made to listen to us, the people who actually use the airport and one of main reason they've got an airport in the first place and not the wannabe Andy McNabs and 007s that run the security companies then nothing is going to change.