I think the point is that while this photograph kind of works (from above, at a distance), generally from ground level it doesn't. So if it only works from above, then is it really useful as a camouflage?

In fact, a 2016 study concludes that the camouflage hypothesis doesn't seem to carry weight: https://www.ucdavis.edu/news/zebra-stripes-not-camouflage-new-study-finds