More likely to have been the DfT.
First Great Western wanted to extend Oyster card acceptance from the Greater London boundary station of West Drayton to stations further west that were likely to be used for sailing events at the 2012 Olympics - but DfT said no.
I doubt it was Herts County Council as Cheshunt and Broxbourne got Oyster. But I do recall a fuss about St Albans, and that would be Hertsmere Council. Maybe that was it?
The gates at Hatfield are all equipped for smartcards whenever it can be sorted.