It is un-acceptable and un-necessary to inspect every bl**DY UK/EEA passport/ID card however thats what the UK government wants and believes is in the national security interest (Political and xenophobic b*llo*ks!)
Its even more so because UK Borders are in receipt of pre-clearance and detailed passenger lists for every UK bounds flight and have been for many years.
This gives them more and a little opportunity to meet and greet suspect or other persons of interest at the gate if they see fit whilst leaving the majority of legally travelling persons to go on their way !
As for customs checks for contraband thats a differing matter.