@Orestes:
Interesting! The long parallel marks are not visible at all in the photo to which you linked ... but very clearly visible in more than one photo, including
this one from susier.
It seems to me that the crucial difference among these images, is that yours (the one showing no marks) is some combination of the perspective angle, and the position of the sun when the photo was taken.
The images showing the marks have brightly highlighted regions, in which the surface is reflecting the sun toward the camera. The image to which you linked is "flat" in terms of illumination: no strong highlights.
On this basis, my interpretation is that the marks are NOT paint scrapes, but rather contours in the VS skin (presumably furrows, but possibly ridges). This would explain why they don't show under different light angles.
If these are skin contour marks, then I suppose they might be the consequence of either:
(a) object(s) indenting the skin (but not removing the paint) as they flew past
or
(b) wrinkling of the skin, perhaps due to extraordinary deformation under the forces of the calamity
Somehow, (b) seems more probable. I've seen a number of examples of skin wrinkling on old non-pressurized planes, which didn't look anything like the patterns on the VS. But the fuselage skin on those old birds was mainly there to keep the wind out, and the construction of an A321 stabilizer is a world apart.