I agree with most of the article about academic environments being open to vigorous debate among opposing ideas. But I find this phrase: "diversity of thought" problematic.

Not because I don't actually value diversity in philosophies or modes of thinking, but because the phrase itself has been used recently as a weasel phrase by reactionary forces acting to scale back decades of work to improve actual diversity of backgrounds including race, national origin, genders, sexualities etc. in the workplace and positions of power. I'm not accusing him of using it deliberately in that sense but I think it's important to keep that connotation of this phrase in mind while discussing his talk.