Usually the beliefs being excluded are things like "white people are superior to all others", "there is no reason for the English language to have different words for sex and gender", or "it's acceptable to use terms for immutable characteristics as insults", etc.

And let's be honest - those ideas are excluded in the name of inclusivity. If you interpret "inclusivity" as meaning "accepts everything", you end up at a paradox quite quickly. It's the paradox of tolerance, yet again. And its cause is the same thing: misunderstanding the goals based on a naive reading of the name.

Inclusivity isn't about including absolutely everything. It's about maximizing the variety present. And doing that does have the cost of rejecting people who drive others away.