It's true, most good programmers won't choose a language based on just syntax. And even though most economists aren't good programmers (in my experience), they're still smart people who can see past the syntax.

The paper is probably misusing the term syntax though. C++ and java really are quite similar in many ways, far beyond just syntax, java just letting the programmer forget about some annoying things like memory management and portability. If most of what they're doing in the language is numeric analysis, then there probably isn't much of a difference at all, and they will probably get slightly better performance from C++.

Plenty of people claim they won't use Python for its whitespace. Not quite the same, but it seem that elements of syntax are influencing peoples decisions.

I would also recommend Python to new programmers, partly for the syntax.

I get what you mean, but lots of languages have seen limited popularity due to their unfamiliar or odd syntax (e.g. lisp).