Yes...it is a question of proportion. And often when Angie makes that comment she is looking at a pair of trousers that are already shorter (i.e. "ankle length") but not at the RIGHT length for the wearer, to her eye. In other words, the pants are in some "no man's land" length, neither cropped enough to appear cropped on the wearer, nor long enough to look full length.
And/or the pants are not tapered enough at the ankle for their length, and Angie perhaps thinks they'd look better rolled, so they would taper more.
Another factor to weigh in the balance -- with a lower contrast pant and/ or footwear, rolling won't make the leg line look shorter. With higher contrast, it may.