Earlier quoted context omitted.
Ah, but remember that in this example everyone sees the posting (or, if you prefer, the recruiter only reaches out to women who see the posting) so your scenario is impossible. The recruiter's role isn't to increase visibility but rather to be a signal to women that they wouldn't be wasting their time with this company. When programs like the one briefly mentioned in the article are done well their net effect is real…
Both of the students are CS majors. They presumably will both eventually work for similar companies. Why would the woman who is equally interested in computer science pass over the job posting, requiring an actual recruiter to be present, when the man does not? Do women get CS degrees and then leave to work in some other field post-graduation, not writing code? If so, that is a huge problem. Do they lose interest in…
However, your second paragraph sort of has things backwards. The current scheme of things strongly signals to women (pretty accurately) "your odds of getting hired are lesser than your equally talented male friend." Such signalling as I described before isn't about saying that their odds are better than their male friend but rather that the company is actively trying to not disadvantage women.