It’s why we can have threads about leftists attempting to argue 2+2=4 is not objectively true. Truth is not objective. To them, knowledge is something that is created through language, all subjective.
Its why you have the The National Museum of African American History & Culture publishing this:
A definition of “whiteness”:
This is the source of the racial tension.
Leftists perceive it to be Trump only because he was politically successful in slowing it down.