Atheism too speaks of something that can't be measured: the certain non-existence of the thing every human culture has sensed, longed for, believed in some form or another since the beginning of humanity.
Science itself is full of things that can't be measured. The Fermi Paradox and the Great Filter are examples of this: we theorize about why earth -- despite 100 billion-billion other planets like it -- appears to contain the only life in the universe. The theories include those of super-intelligent life beyond our measure, which really isn't that far intellectually from the idea of God.
The article does not claim Christians are better scientists than atheists. Rather, it corrects the idea that these thinkers' religion was an incidental primitive flaw in an otherwise great mind, when in fact, these men's insights into and pioneering in their scientific fields were driven by philosophical commitments to the divine origin of the universe.