Just move on folks; nothing happening here.
BUT count on the irrepressible David Horowitz to turn the whole thing on its head. (Why they always go to him for a comment is beyond me.)
In the Horowitzian, fact-free world, such studies prove nothing because we already know that there is a liberal bias in higher education and higher education simply hides this fact on all occasions. Here is Horowitz's argument:
"The experiment focused on how college administrators handle an activity in which they are likely to try to hide any political bias they might have—much, he said, as he believes professors who abuse bright conservative students in class go on to give them good grades to demonstrate their own fairness."
Now, this could help explain why Horowitz's attempt to locate college students in Pennsylvania with complaints about having been mistreated by liberal professors came up empty. Evidently, the best way to get a good grade is to be a conservative student. Faculty are not fair; they just give right-wing students good grades to prove that they are fair.