Nothing to do with the revesers not stowing, it is simply a recognition that it takes less runway to stop after reverse is selected, than it takes to stow the reversers and then accelerate to lift off speed.
The advice is for pilots that may see a runway blockage, or the end of the runway comming up, and think that they have a chance of avoiding an accident by getting back into the air. Taking this option will merely increase the speed that you crash at.