I think the ruling is probably much more complicated than the simple statement that it was on pose alone. Whether or not the similarities between the original and derivative work meet the criteria for the Luxembourg equivalent of Fair Use is probably a better discussion.

However either way, I see no reason to think about copyright in such a limited way. I don't think many people believe that copyright is only enforceable if two works are exactly the same. Rather I think they're simply discussing how inspiration and imitation is very common in art.