nnco
FIREWALLing the throttles first has been the drill since primary training
I think the clue to answering your concerns is in your own words above. What is taught in primary training is naturally relevant to (and optimised for) the sort of aircraft used for primary training as well as the pilots experience at that stage.
I would see the advice you are concerned about as emphasising what experienced pilots should already appreciate when flying aircraft with a low thrust line and not as something new.