I have grave doubt about that picture. First if at all it is the left wing it is the tail end and the op of the wing, not where the foam should have hit (it would have hit under the wing, the thermal tiles). Try and look out of a window of a space shuttle, I doubt the wing will be seen like that, the wing is far in the back, the only part of the wing visible from the window is probably the front part of the wing. This should be at a very sharp angle and covered with carbon/carbon composite (pitch black), no way you will see any cracks on it. This must be some floating artifacts within the cabin obstructing some of the window's view. I am surprised at Maariv for their explanation. Apart of that, since it is the bottom of the shuttle that takes the brunt of the heat dissipation during reentry, what is on the top of the wing is of little importance.
Zeev