From the article: "academic staff will grant to The Trustees of Princeton University “a nonexclusive, irrevocable, worldwide license to exercise any and all copyrights in his or her scholarly articles published in any medium, whether now known or later invented, provided the articles are not sold by the University for a profit, and to authorise others to do the same.”"

That means unless a waiver is given, it doesn't matter what the journal does or thinks, the university can publish the material anyway it likes. A compromise of sorts, but the effect is that more people potentially have access.