This is why AA men and women have significantly worse healthcare outcomes, or why women are more likely to die in a car crash.
Yes, maybe it's slightly inconvenient to write a diversity statement. But it's because of these types of initiatives that we're able to build more equitable research and improve outcomes for a variety of minority groups.
So, I guess what I'm trying to say is, suck it up. Or, at least, understand why they're asking for it instead of assuming it's some sort of strange, convoluted, personal attack on your character.