They do but they need their cars to go to work and afford a living. It's usually not a lifestyle choice like an inner city dweller could choose to take public transport or a bike.
They also choose not get married or not having children or only have one child, which all have negative impact on the society. They think a tiny apartment is good, depending on bike or public transportation is good, only because they don't want raise children.
Or do they tell themselves that the child they can’t afford would have been bad for the environment/society so it feels like they’re in control? “Sour grapes” is literally as old as Aesop’s Fables, if not even older.