They haven't precisely banned him, just imposed a lot of onerous conditions on the speech organizers, Young Americans for Freedom.
The university notified the students that because of Shapiro’s “controversial” subject matter, they would have to pay more than $620 for security officers.Needless to say, the university has not imposed the latter "equal time" condition on anti-white speakers like Cornel West, Angela Davis, and Tim Wise.
. . . .
An email from university President William Covino told student Mark Kahanding that the event was canceled.
Instead, he said, Shapiro could speak at another time when his voice would be tempered by speakers selected by the school.
“I have decided that it will be best for our campus community if we reschedule Ben Shapiro’s appearance for a later date, so that we can arrange for him to appear as part of a group of speakers with differing viewpoints on diversity,” Covino ordered. ["Campus Fascists" Take Over: University Cancels Conservative Speaker by Thomas Lifson; WND.com, February 23rd 2016.]
The university's Social Science wing responded to the scheduled speech in the spirit of scholarly collegiality that nowadays pervades that side of the academic enterprise:
After hearing about the event, sociology professor Robert Weide called the YAF students “white supremacists” and invited them to fight him.It's outrageous, of course; but Ben Shapiro himself seems to be quite willing to join a witch hunt against "legitimate racists":
Rubin: You would agree that racism exists? That there are people that are legitimate racists?The key question here is of course: Who gets to define "legitimate racist"?
Shapiro: Of course. It would be idiotic to think otherwise. Of course, there are legitimate racists, and we should target them, and we should find them, and we should hurt their careers.
[Ben Shapiro on Free Speech, College Campuses, and the Progressive Left; The Rubin Report; February 18th 2016; my italics.]
Five minutes googling failed to turn up anything Shapiro wrote in defense of Jason Richwine; but if any reader with more patience than me can find something, I shall post it here.