Google is Google. They hire _VAST_ numbers of people straight out of college. It's practically a pipeline for them. I am not saying that neglecting referrals from professional contacts doesn't work for Google, but rather that it's commonplace and "good enough" for other places.
Moreover, from the point of view of an individual rather than the employer's performance metrics, it's generally better to make a human connection if you're just talking about the chances of getting hired.
I don't see what good references are since the applicant gets to choose them. How many people legitimately can't find a single person from a previous job to list as a reference? Or find a person that can convincingly pretend to be a reference.
It would be different if you could randomly call 3 people they worked with at their last company, but I don't think anyone does that.
Moreover, from the point of view of an individual rather than the employer's performance metrics, it's generally better to make a human connection if you're just talking about the chances of getting hired.