The ADL changed its definition of "racism" last year from the real definition to the fake, liberal arts college, leftist definition. Namely, it went from referring to racism as an individual's conscious beliefs and actions that people are superior simply based on race to the idea that it's about structures that favor whiteness -- if you're on social media, you probably see people operating under the fake definition of racism a dozen times a day.
To the ADL's credit, they realized a component of the problem with the fake definition fairly quickly. Namely, they realized that under their revised definition, Whoopi Goldberg was technically right in saying that the Holocaust wasn't racist even though Hitler himself explicitly viewed Jews as a different race. This aspect of the definition really falls down like a house of cards when the people who believe this definition to be true also attack Goldberg for her comments. The Chinese government's actions against the Uyghurs can't be called "racist" under that definition because there aren't any white people involved. You couldn't say that the Arminian genocide was racially motivated.
In order for people to keep this definition propped up, they invented the concept of "white adjacent". Basically, the definition is still valid even when the bad actors aren't white because they're still white adjacent. Asians and Jews generally perform better than whites in the Western liberal system because they're behaving white.
Of course, this is where believers in this definition start to run into David Duke territory. The presumption that behavior is innately driven by race and that race should change our expectations of how individuals would act is shared with KKK. It's the espousal of this definition that lead to the LA Times to refer to Larry Elder as the black face of white supremacy -- he's a black guy who isn't behaving how they expect or want black people to behave. George W Bush referred to the "soft bigotry of low expectations" in reference to Muslims. That's not soft bigotry, that's out and proud racism.
The only difference between these people and the Klan is that they want to hold the pernicious beliefs while virtue signaling by shaming anybody who uses stereotypes, even in a joke.
That poster at the Smithsonian about white behavior was there because a lot of people really believed the bullshit. Still, if it's true that there's white behavior, that means that there's non-white behavior. That means that a lot of stereotypes aren't just true but that they're manifestations of the DNA of different races of people. If these people really regard Larry Elder to be an "Oreo" or they're referring to Thomas Sowell as "Uncle Thomas" (yes, I've seen that) and they really believe that people should act their race, they don't have a leg to stand on when they complain about a comedian making a joke about Asians being bad drivers.
Really, the best option that they have is to espouse a philosophy of, "It's true; but, you shouldn't say it." That's pretty much a whole philosophy of lying. Still, they can't do that because they want to keep attacking people of color for not acting their race. So, what is it now? It's wrong to make a joke about a race but it's perfectly fine to express genuine racism? Oh, wait, we're doing away with the old definition of racism; so, it's no longer racist for a white person to use racially insensitive speech toward a person of color so long as the person of color is acting white, right?
Yeah, I think that this comes from their bullshit definition and the conscious attempt to make racism a more abstract issue in order to gain political control.