A worrisome initiative at Columbia U

Columbia University is adopting a diversity program that sounds like establishing a idealogical litmus test. Todd Zywicki comments:

One important effect of imposing this sort of ideological litmus test for hiring, is that it makes it increasing difficult to protect academic freedom from bad ideas such as David Horowitz's Academic Bill of Rights. The objection to the Academic Bill of Rights--an objection that I share--is that it improperly infringes on academic freedom. But if Columbia is going to override its academic freedom policy for these political purposes, then there seems to be no principled reason not to override academic freedom for the political purposes favored by David Horowitz and other advocates of the Academic Bill of Rights. What can Columbia say in response to Horowitz now?