http://www.npr.org/blogs/health/2013/10/03/228859954/some-online-journals-will-publish-fake-science-for-a-fee
The other half of the story, from the same link: Bohannan says the exercise is a damning indictment of the way peer review works (or doesn't) at many online journals. Peer review is the time-honored system of having outside experts comb through submissions to identify flaws in method, data or conclusions. It's the way scientific journals do quality control. "Peer review is in a worse state than anyone guessed," he says.
I would assume the "peers" either were not actually informed on the subject or did not read the papers
I assume he sent out 300 and that a few were like vanity publishing sites (pay to be published) and most were peer reviewed that just failed to do the job.