Yes I'd agree that driving isn't active travel but according to the BBC:
"Mr Matheson said the council's long-term aim was to "see cycling as the biggest participation activity in the city by 2020".
With no mention of travel I read this as either a pastime which people are engaging with such as playing golf, going to the gym, stamp collecting etc or a broader categorisation of anything a person might be doing at a time rather than being physically active.
So one way I would read this is to categorise leisure cycling, go-karting, etc as activities and exclude commuting/driving as bike/car use. Otherwise I would include utility bike use then struggle to find a definition which stops driving from being an activity.