A couple points.
- “ It’s not that campuses need to purge Marxists as much as they need to let a few more Ayn Rand aficionados and ethno-nationalists onto the tenure track…” is a Straw-Man argument. Desiring to see conservative and free-market ideas debated and presented fairly in universities is not necessarily arguing for ethno-nationalism or Ayn Rand’s objectivism. All conservatism is not the fringey stuff.
- Arguing for ideological diversity as a response to calls for ethnic diversity is a result of the basic premise that ethnic differences are negligible. If a black person and a white person are essentially the same biologically, then the differences must be cultural and ideological. In that case, cultural and ideological diversity are clearly more important than diversity based on the genetic quirk that causes differences in skin color. Of course, if you want to argue fundamental differences between people of different races, you and Mr. Murray might agree on more than you suppose… on the other hand, if you believe, as I do, that the greatest difference between two people is the choices that they make (which are, of course, informed by the circumstances fo their life, but not totally controlled by them), then having people who have made different choices and follow different political philosophies is really valuable.