There is a strong racist ideological movement against "white people" in modern academia and society in general, and the ADL is fully aligned with this.
Reading the Wikipedia and nothing else, Whiteness Theory just seems to try and identify and define the concept of a “white” racial group and the notions associated with that group.
It’s pretty neutral.
And it’s interesting because by default people are ethnocentric, and don’t identify strongly with large groupings like country or race.
This is just the racial equivalent of a text describing the emergency of nationalism.
[Whiteness is a condition one first acquires and then one has\-a malignant, parasitic-like condition to which "white" people have a particular susceptibility. The condition is foundational, generating characteristic ways of being in one's body, in one's mind, and in one's world. Parasitic Whiteness renders its hosts' appetites voracious, insatiable, and perverse. These deformed appetites particularly target nonwhite peoples. Once established, these appetites are nearly impossible to eliminate. Effective treatment consists of a combination of psychic and social-historical interventions. Such interventions can reasonably aim only to reshape Whiteness's infiltrated appetites-to reduce their intensity, redistribute their aims, and occasionally turn those aims toward the work of reparation. When remembered and represented, the ravages wreaked by the chronic condition can function either as warning ("never again") or as temptation ("great again"). Memorialization alone, therefore, is no guarantee against regression. There is not yet a permanent cure.]
"Whites learn to be white. That suggestion by Thandeka is that whites are not born white. They have to become white. And her suggestion is that white children who were not white originally - they were born human. Little by little, they have to be abused into becoming white humans. And this abuse is sometimes physical - of being physically disciplined into whiteness, such as being bullied into whiteness. That's a phrase I like to use, whiteness as bullying, but it's also psychological and cultural, and it becomes with caretakers and guardians. Not the least of which - the more important caretakers are of course the white family, parents etc. but it extends to the white nationhood as a caretaker, the white social system, the white social welfare, the white governance system. They also discipline and abuse white humans into whiteness."
— Education professor Zeus Lombardo
as a couple more egregious examples. The extra fun part is that the terms are chosen that you can talk about white people and whiteness as horrible evils, or how Noel Ignatiev said we should "abolish the white race" and when people understandably get offended, you can say it's just a concept, why so angry. That wouldn't fly with any other ethnic group.
Beyond the over generalized statement that racism was invited by white people, there is nothing wrong with the book.
If it’s really for 4 year olds, even that statement might be fine rather than delving into the complexity of what systemic racism is, and why it can exist against white people in other nations where they are a minority.
Simplifications happen all the time in books aimed at preschoolers. For example, they would usually teach that America was “discovered” or that Native Americans and the settlers got along in thanksgiving harmony and nothing else.
https://en.wikipedia.org/wiki/Whiteness_theory
This is the issue that Elon Musk is concerned with.