He says: 'Only the upright posture is really suitable for a pleasant journey by bicycle.'
'A well designed chair supports the natural curve of the spine. The lumber support seen on car seats and modern office chairs encourages the spine to curve into its natural ‘S’ shape.'
So 'would you drive more if your car had a saddle?' is the question I like to ask those who doubt the worth of a seat on a bike.
I think he's trying to blend two very different things. Wind resistance matters - although for bikes used to potter 2 miles the extra exercise might be seen as a benefit. 20 miles into a headwind is a different matter.