To my understanding (and as a disclaimer, I advocate strongly for it), "inclusivity" in general means making an environment safe for people of marginalized backgrounds. So to me, his declaration that inclusivity as a value ought to be up for debate seems to indicate he doesn't think it's a top priority that students of marginalized backgrounds feel welcome in his classroom.
Is that a jump? A bit, but it's based on seeing similar situations play out in other areas.
But the choice of curriculum was to my second point: I think students deserve the chance to study a wide variety of history and literary viewpoints, including when feasible some from backgrounds similar to theirs. There has been tons of literature written by black authors, written by women, written by LGBTQ folx. Often times those works have been, in the past, deliberately destroyed (like the Institut für Sexualwissenschaft) or not considered for publication (George Elliot choosing a pseudonym to publish outside romance), which is a significant component to why there are so many more white men authors historically.
If you teach a course where all the literature you choose is from white men, you really limit what history you are teaching, and you can subtly reinforce that others may not be welcome to succeed in literature. Inclusivity asks us to consider those implications and pick some variety of authors--there are many great writers of so many different backgrounds to choose from.