It may not be adhering to one part of the wing, but could be adhering to another. You won't know unless you clear the whole wing on the ground, or just takeoff to see if it clears. If it doesn't, well, too late.Sec. 121.629 — Operation in icing conditions.
(a).........................................
(b) No person may take off an aircraft when frost, ice, or snow is adhering to the wings, ............................
That argument could be made. If you look at the video you can see that they cleared a portion of the wing to see if it was adhering.