The Pebble In the Shoe Argument

I see liberals occasionally make the "why do you make such a big deal out of DEI" defense. Basically, yes it's stupid, but it's small potatoes. Here's that argument again - that DEI empowered Trump because it irritated so many people like a pebble in the shoe. But if you take this framework, the really interesting question is why couldn't liberals course correct? What made it impossible for liberals to take the pebble out of the shoe and preserve the "good" aspects of so-called diversity. Why did they always go down the maximalist route? This will tell you a lot more about the world.