That one raised a laugh of 7/10. Effects of controls Part 2 when learning to fly as a PPL demonstrates the absurdity of that statement.
The statement may have been absurb...but effects of controls Part 2 when learning to fly as a PPL does not demonstrate that it is absurb...far from it, if when gliding a light aircraft with drag flap you subsquently lift the flap the gliding distance will increase.