It is accurate. The reason he says ignore the wobbly bit is that curve he is evaluating is a trim intersection (do a duplicate curve on that trim edge, and you will see it is inherently nasty in order to maintain G0 continuity.
BUT you ignore it because that entire edge will be deleted and replaced by a fillet.
Trim edges are just nasty by their nature - it’s why you want to avoid building geometry off trim edges whenever possible, and why many times when you see student work it looks horrendous with a billion isoparms, because they will trim a curve, and then create a surface between two trim edges instead of building a clean surface.