In the answer you linked, the reference to scooping meant to keep your pick close to the strings as you move up and down the neck as opposed to allowing your picking hand to "scoop" (drop) below the neck.
This advice applies to playing fast picking runs where you don't want any wasted motion slowing you down. So you don't want your pick to stray too far away from the strings you will be picking.
It does not refer to the picking motion itself (which would be perpendicular to the strings) but to your hand position as you move to different places on your fretboard.
To use an analogy - if you are playing a fast run on the 2nd and 3rd strings - pretend like those are the rails of a railroad track and your picking hand is the train. Don't let the train get off the track as it moves back and forth to play higher or lower notes on the fretboard.