Speed is Life
Up and away there is ample stall margin during maneuvering, but during takeoff there isn't much to begin with. Maneuvering in pitch as the aircraft is lifting off reduces what little stall margin there is, especially at heavy weight when acceleration is slower. A reduced rotation rate and the addition of speed above Vr before lifting off significantly increases stall margins, especially if the wing has been contaminated. An intuitive pilot would reduce his pitch rate and add some speed on takeoff if there were any possibility of a contaminated wing, even after de-icing. This technique seems to be the exception rather than the norm. Pilots tend to fly the way they train, and pilots are typically trained to fly as though the engine were going to fail just after V1 on every takeoff. Speed is life.