It's not a "requirement" if it's not actually required. I can guarantee you that if someone were to go into, say, silicon valley and find every single developer who got a job in a role which was advertised at some point using the word "rockstar" or "ninja" and then compared the average talent/skill of that pool of developers vs. developers as a whole there would not be much difference, if any.
Edit: I think I slightly misread your post, so you have my apologies.
It is much in the same vein as the silly "requirements" of x years in y, z years in w, etc. And a stack of degrees. Usually it's just a way to keep the walls high to weed out the truly unqualified.
No, I understand it can't be formally understood as a requirement - but that's how it's phrased. Hence my comparison with todays unrealistic "requirements".
Edit: I think I slightly misread your post, so you have my apologies.
It is much in the same vein as the silly "requirements" of x years in y, z years in w, etc. And a stack of degrees. Usually it's just a way to keep the walls high to weed out the truly unqualified.