True, but whether someone self-identifies as Jewish depends on exactly how you ask him. To compare the Jewish representation in the US population, college X, and college Y, it's important that the same definition was used.

Feynman (mentioned in Unz's article) famously objected to being labeled as a Jew or Jewish scientist, since he was unreligious and didn't like the speculations about race and ability.

He used Jewish surnames. His analysis, IIRC, did not control for the fact that top American universities foreign enrollment had been increasing steadily for a long time.

The implication is that Jews are gaining advantages from an ethnic network. Discussing even the existence of such a network is not considered acceptable in the West.