The article convinced me that starfish bodies developed from heads, just as I'm convinced that primate arms developed from legs, but it didn't convince me that it's appropriate to call the modern forms of these things heads or legs.
If you instead relate to the organism in its present form in some more mundane ways then it might not seem that way.
Analogies are failing me, but perhaps it would be like realizing an entire government basically spawned out of the centering concept of religious freedom. The structure of it then makes a lot more sense.